The Role of Instagram Influencers in Affecting Purchase Decision of Generation Z

Objective – Currently, social media is an online communication tool that made a huge impact on society. It makes social media a means for companies that want to attract the attention of potential consumers by utilizing the role of social media influencers who are considered to have great power and influence in the online world. An influencer could evaluate a product that consumers would admire, encouraging them to purchase it. A social media influencer has a significant role in consumer purchase intention. Hence, it is essential to analyze a factor that might affect a customer’s purchase intention. Therefore, this paper will examine the effect of Instagram influencers on customer purchase intention for Generation Z in Jakarta, Indonesia . Methodology – An online questionnaire was used to collect the data from 162 respondents who are active Instagram users, currently living in Jakarta, following at least two Instagram influencers, and have purchased a product/service reviewed by Instagram influencers at least once. Findings – The findings indicate that Instagram influencers’ expertise and trustworthiness significantly affect customer purchase intention. Therefore, marketers and entrepreneurs in all sectors need to consider and engage with Instagram influencers as a strategy to increase customer purchase intention, particularly when planning to target Gen Z in Jakarta, Indonesia. Also, it can help them evaluate the long-term impact that Instagram influencers may have on their business. Novelty – This study will give a deeper understanding regarding the influence of influencer’s credibility, expertise, and trustworthiness toward Gen Z’s purchase intention.


I. INTRODUCTION
Currently, social media is an online communication tool that made a huge impact on society (Hermanda et al., 2019).This makes social media a means for companies that want to attract the attention of potential consumers by utilizing the role of social media influencers who are considered to have great power and influence in the online world.An influencer could evaluate a product that consumers would admire, encouraging them to purchase it (Hermanda et al., 2019).A social media influencer has a significant role in consumer purchase intention.As the impact, companies that use an Instagram influencer to promote their products can reach a wider market due to the high number of followers on their Instagram accounts.By taking advantage of the existing situation, being an Instagram influencer can be considered a primary job in the workforce.
Instagram influencers are Instagram users who have the unique ability to attract people's attention and influence others with credibility in a large audience.Commonly, an Instagram influencer has many followers on their accounts that support their high engagement rate.The high number of Instagram users makes influencers a new trend in the workforce.Someone can change their career with the fame they have on social media.In the current industrial revolution era, anyone can influence many people and even become a trendsetter, which means that everyone can be the center of attention (Maulana et al., 2020).
The credibility of Instagram influencers plays an important role in the marketing process.Social media influencers are regarded as more credible, trustworthy, and knowledgeable due to their amiability in building rapport with consumers, especially for businesses that target the younger generation (Al Kurdi et al., 2022).Companies that use endorsement services through Instagram influencers must understand the target market they want to reach because each influencer has different characteristics according to their respective expertise, which will later influence consumption pattern and purchasing power of the consumer.
There are many advantages that Instagram has today to being a marketing tool for Instagram influencers-starting from the ease of spreading content or information on a product without being constrained by distance.It makes buying and selling products easier because people can access information about the products they want quickly and from reliable sources.It was supported by a high level of trust in social media, as much as 51% in 2018 (Maulana et al., 2020).Therefore, there is a possibility that the existence of Instagram influencers affects the purchasing power of customers.
Customer purchase intention is one of the important factors that can help any business activity run smoothly and sustainably.It can be defined as the preference of customer willingness to act to buy a particular product or service in a specific condition.Nowadays, many companies try to understand their customers' purchase intentions to help them achieve an effective marketing strategy.The company can easily differentiate what marketing strategy is suitable for each customer based on this indicator.
Generation Z, also called Gen Z, is the generational cohort after the Millennials were born between the late 1996s and early 2010s.Many people also call this generation as iGeneration since they are the first generation born in the era of internet and technology development where people can be easily connected worldwide through the social media platform.That has become one of the reasons why we tried to analyze Gen Z in this research since they have also become the highest Instagram users in Indonesia.
Based on the discussion above, we are interested to know the relationship between Instagram influencers and customer purchase intention.Therefore, this study will examine the importance of Instagram influencers affecting customer purchase intention for Gen Z in Jakarta, Indonesia.According to the problem background above, the research questions of this study are: (1) Does Instagram influencer's credibility significantly affect customer purchase intention?(2) Does Instagram influencer's expertise significantly affect customer purchase intention?(3) Does Instagram influencer's trustworthiness significantly affect customer purchase intention?The objective of this research is three-fold: to examine the effect of Instagram influencer's credibility on customer purchase intention, to examine the effect of Instagram influencer's expertise on customer purchase intention, and to examine the effect of Instagram influencer's trustworthiness on customer purchase intention.

II. LITERATURE REVIEW
A customer's purchase intention refers to the degree to which the willingness of a customer or preferences to buy a certain product or service.Mirabi et al. (2015) stated that purchase intention is a kind of decision-making that studies the reason to buy a particular brand by the consumer.Customer intention can be used to predict actual user behavior, and it becomes the best predictor of a person's behavior since it contributes to a better understanding of a customer's actual behavior (Wibowo et al., 2020).In many business activities today, understanding customer behavior has become an important sector that needs more attention.Furthermore, many businesses today have put great attention to understanding its customer to generate more sales and acquire customers as many as they can.
Purchase intention generally can be measured by using four indicators: planning to buy, allocating budgeted money to buy, considering buying, and having a strong desire to buy (Arifani & Haryanto, 2018).All of that can be classified into more specific based on types of customer purchase intention, such as informational intent, investigative intent, navigational intent, and transactional intent (Peterson, 2021).Informational intent is the stage where the customer is willing to gather the information to find the answer on a certain product which later affects their awareness.While investigate refers to how the customer responds to the information they have gathered before-for instance, comparing the option available on the market with some consideration such as price, product review, etc. Navigation intent represents the customer who is trying to visit the store of the product they are looking for.Lastly, customers with transactional intent will obviously be closer to the conversion stage since they are willing to make any transaction and tend to buy.
Besides, one of the important factors that can influence customer purchase intention is the attitudes of others.According to Kotler and Armstrong (2014), if someone important to you suggests that you should buy the cheapest car, then your chance of purchasing a more expensive car is reduced.It shows that the role of other people can be taken as the consideration factors that influence customer purchase intention.
Generally, influencers can be defined as someone within the niche or industry who has the ability to influence others' behavior or purchasing decisions due to their specialized knowledge, authority, position, or insight into a particular subject.Influencers play an essential role in many businesses' activities related to marketing.Many companies use enticing figures such as athletes, celebrities, and public figures to help them promote and sell their products through several channels, including television, radio, and the most updated one, which is social media (Lou & Yuan, 2018).Nowadays, the high trend of social media has brought influencers to become more popular.
In Indonesia, the trend of the term influencer is crowned to a YouTuber, Tiktokers, or celebgram, which refers to someone who has the ability to influence the public due to high followers on their social media accounts.A celebgram is the term for an Instagram influencer who has large number of followers on their Instagram accounts and has a significant influence on business.If someone want to use celebgrams, they should pick one with a huge number of followers so that they may reach larger audiences (Pangaribuan et al., 2018).They not only convey information but can also influence their followers through various interactions carried out on social media.That way, they take advantage of the power they have on social media to be able to carry out a promotion, it can be services or products by leading public opinion to use and buy the product or services being promoted.
This phenomenon of social media influencers in Indonesia has risen significantly, which can be said to have a significant influence on people's consumption patterns (Al Farasyi & Iswati, 2021).The high intensity of people's purchasing power towards the promotional products of influencers has a powerful impact on the growth of the digital economy.Indeed, not all products promoted by influencers have achieved the desired sales targets.There are several factors that influence the success of a social media influencer in helping businesses to increase sales of a product.In other words, it affects consumer purchasing power.Social media influencers must have the attractiveness, trust, and expertise that can lead their followers to follow any suggestions and arguments they share with their followers on social media.Trust leads to the ability of sources who have honesty and integrity and can be trusted (Sugiharto & Ramadhana, 2018).That way trusted social media influencers can easily influence their followers to carry out the endorsement process.Credibility refers to the degree to which individuals believe and trust what other people and organizations say about a specific product or service (Agyei et al., 2020).Expertise refers to the knowledge, experience, and abilities in relation to the information offered by communicators (Safitri et al., 2021).Meanwhile, the level of assurance in a communicator's intention to convey the claims he believes to be most reliable is known as trustworthiness (Ericsson & Håkansson, 2005).
It is important to ensure that the products offered are in accordance with the characteristics of a social media influencer so that the target market to be aimed at is also in accordance with the vision of the product.The characteristics of the influencers must match the products they carry, and if the audience feels attracted to influencers, this can easily persuade through the interests of the influencers (Sugiharto & Ramadhana, 2018).It is likely to happen to social media influencers who have many followers on their social media accounts.In general, not a few companies make social media influencers brand ambassadors for their products.It aims to increase awareness through education of target consumers about the products offered with output that can increase sales.
The importance of social media influencers cannot be separated from how they present themselves through their social media accounts.Credibility is self-branding, or personal branding, is a form of marketing that an individual uses to create a uniform public image that demonstrates their values and overall reputation (Shindy & Hariandja, 2020).It helps us build a theoretical study of the relationship between the importance of an Instagram influencer and a customer's purchasing power.Based on this theory, good personal branding owned by Instagram influencers helps them do product marketing.Consumers' trust in Instagram influencers makes them dare to decide to buy a product suggested by influencers without having to take samples first.With consumer patterns like this, it greatly impacts the level of product sales of a company that uses Instagram influencer services to carry out a promotion for their products.According to Audia et al. (2018), in 2014, the popularity of Instagram as a marketing platform surpassed the popularity of Facebook and made Instagram a very powerful sales tool (Audia et al., 2018).This is what makes it easy for Instagram influencers to do marketing that has an impact on the high purchasing power of consumers for a product or service that they are promoting.
Nowadays, the trend of online shopping is very popular among Instagram users.With the help of Instagram influencers, it is beneficial for online shop owners to increase their sales from the results of promotions carried out by Instagram influencers (Ratnapertiwi et al., 2021).This marketing strategy is very useful for conveying messages to consumers by utilizing Instagram influencers as communicators.That way, their influence greatly impacted the decisions and interest in buying the product being promoted.In other words, Instagram influencers can be said to be spokespersons for a brand or product that can attract consumers to purchase the product.In addition, they are also actors representing the target market segment.
Audia et al. stated that elaboration likelihood theory explains that humans elaborate or are influenced by a message when they think about what the messenger said, evaluate the arguments in the message, and react to the advertisement (Audia et al., 2018).A consumer will trust what is said by Instagram influencers if they feel that the endorser can describe the identity of a product well.Some of the things those Instagram influencers do to attract consumer purchase interest are to attract the attention of their followers by interacting on social media to increase their followers' buying interest.After they have succeeded in getting the target market's attention, there will be a special attraction for their followers or consumers to have a product that they are promoting as a result of their assessment of a brand or product.This reaction raises the desire to have an effect that is being offered until the purchase process occurs for the item being promoted, which is a form of action taken by consumers.
Gen Z is the abbreviation for the generation of people born in the late 1996s and ended around the 2010s.It means that in 2021, this generation will have a range of ages between 11 and 23.Gen Z is the real digital native generation since they are born in the development era of technology, the internet, social media, and the rise of the smartphone.It is no wonder that this generation is often called iGeneration.According to Desjardins (2019), 98 percent of Gen Z own a smartphone, and 92 percent of them have a digital footprint.It is proven that most of this generation exists on the internet and is connected online.Therefore, many of Gen Z enjoy doing some activity on the internet and communicating through social media as they grow up entirely in the digital era.The population of Gen Z in Indonesia is predominated since they have an average time spend of 8.5 hours per day on the phone, which is higher than most countries with only 2 hours a day, and they also spend more time on social media (Kim et al., 2020).

Hypothesis Development
Kemeç & Yüksel (2021) discovered that Instagram influencers' credibility had positive effects on purchase intention.Based on the previous studies in the literature, the first hypothesis of this study is as follows: HI: Instagram influencers' credibility is a significant factor affecting purchase intention.
Botelho (2019) stated that the result of the study indicates that social media influencers' expertise affects the individual's purchase intention.Based on the previous studies in the literature, the third hypothesis of this study is as follows: H2: Instagram influencers' expertise is a significant factor affecting purchase intention.
A past study conducted by Saima and Khan (2020) shows that trustworthiness had effects on purchase intention.Based on the previous studies in the literature, the second hypothesis of this study is as follows: H3: Instagram influencers' trustworthiness is a significant factor affecting purchase intention.

III. METHODOLOGY
This study emphasizes a quantitative approach to answer the research question and prove the hypothesis being made in this study.Using a standardized measure, it will analyze the relationship between an independent variable and dependent variable to provide more reliable and objective outcomes for analysis.
The quantitative approach in this study will show the relationship between two variables which are the independent and dependent variables.The independent variable refers to the controlled variable and influences the dependent variable.On the other hand, the dependent variable is the variable that is tested and measured in the study, which depends on the independent variable.Using a quantitative approach, this study collected the data in this study through a questionnaire.The questionnaire would be given to the target sample representing the total population.
This study focuses on Instagram influencers and their impact on customer purchase intention for Gen Z in Jakarta, Indonesia.The influencer in this study is not restricted to one industry because the primary subject is the impact on the customer.This research started from November 2021 until the beginning of May 2022.This study involved Gen Z with the range age 18-24 years old, living in Jakarta, follow influencers on Instagram, have purchased a product recommended by Instagram influencers, and have observed them engaging in an advertising activity.
This research creates a model framework to illustrate the relationship between the dependent variable, which is the important of Instagram influencer toward customer purchase intention for Gen Z in Jakarta, Indonesia and the independent variable, which is Instagram influencer's credibility, expertise, and trustworthiness.The model framework is shown in Figure 1.
Abie Syahrin Ghalib, Muhril Ardiansyah In this study, we used a random sampling technique.Estimating the number of samples is needed since the population is too big, and it is impossible to sample each member directly.According to Hair et al. (2010), for most research situations, a minimum sample size of 50, preferably 100 observations, is required in multiple regression analysis (Hair et al., 2010).Furthermore, the number of samples were determined based on the result of the minimum sample calculation.The minimum number of samples necessary for this study (number of indicators + number of latent variables * estimated parameters) is 120 (Hair et al., 2010).
This study utilized an online questionnaire as a tool to collect the data for this quantitative research.It also helps the respondents answer each of the questions easier.In addition, respondents may complete this questionnaire anywhere at a suitable time.The questionnaire in this study guarantees the confidentiality of respondent data, encouraging them to answer all the questions truthfully.Since the data gathered is in the form of quantitative data, it may be helpful to compare to another research.
The questionnaire employs 31 questions to identify the characteristics of the respondents towards the variables examined in this study.It will refer to the general background of the respondents and Instagram influencers.The characteristics of respondents in this study comprise three aspects: demographic profile, Instagram influencers, and the effects of Instagram influencers on customer purchase intention.Five questionnaire items addressed about respondent's demographic profiles, including gender, occupation, age, and domicile.Six questionnaire items asked for respondents' exposure towards Instagram influencers.Furthermore, there are 20 questionnaire items required to collect significant information regarding how the Instagram influencers affects customer purchase intention through three variables used in this study which includes, Instagram influencer's credibility, Instagram influencer's expertise, and Instagram influencers trustworthiness.The measurements were adapted from earlier research for their dimensions (Kemeç & Yüksel, 2021;Botelho, 2019;Saima & Khan, 2020).
Selecting an appropriate sort of questions is critical to achieve the objective of this research.The objective of this research is to examine factors of Instagram influencers that can affects customer purchase intention.In this study, the questionnaire scale is based on a Likert scale, particularly for questions involving two variables which are dependent and independent variables.Likert scale is one of the most popular tools used in the research to measure knowledge, attitudes, perception, values, and behavioral changes.It refers to a response that offers various alternatives to determine the respondents' opinion and behavior towards the certain problem being studied.A Likert-type scale consists of a set of statements from which respondents can select to measure their responses to evaluative questions (Vogt, 1999).
The questionnaire should be assessed for validity and reliability before being utilized as primary data.Hence, some respondents from the whole sample will be needed for the pretest.The minimum sample size for the pretest is 30 respondents for this study.As a result, 30 respondents must meet the following requirements to pass the validity and reliability test:

Validity Test
Validity and reliability tests were conducted through data from thirty (30) respondents.Validity tests examine the proportion to which a survey items covers the right instrument that should be measure.This study employs three measurement instruments: Kaiser-Meyer-Olkin (KMO), Bartlett's Test of Sphericity, and Anti-Image Correlation Matrix.Similarly, the reliability test measures the degree to which the finding scores are consistent over multiple occasions of testing, different version of testing, or different raters assessing the test taker's responses.The result of the test should exceed the minimum required for every test to be considered valid and reliable (see Table 1).The variables can be considered valid if the KMO value is greater than 0.5 (Hair et al., 2010).Moreover, a value of the significance level for Bartlett's Test of Sphericity should be less than 0.05 to be valid (Hair et al., 2010).In addition, variables indicator can be categorized valid if the value of MSA (Measure of Sampling Adequacy is greater than 0.5, which the MSA number can be obtained from Anti-Image Matrices (Anti-Image Correlation).Lastly, the research instrument can be considered as reliable if Cronbach's alpha value is greater than 0.6 (Ghozali, 2011).Therefore, the Cronbach's alpha should be greater than 0.6 to conclude that the study's independent variable (X) and dependent variable (Y) are both reliable.
After conducting the validity and reliability tests, it can be assumed that the questionnaire is valid and reliable to be utilized for this research.The questionnaire is subsequently distributed to the minimum sample of 120 respondents.Those 120 respondents do not include the thirty respondents who took part in the validity and reliability tests.

Descriptive Analysis
As one of the respondents' criteria in this study, age is one of the most important information in the demographic profile section.The data collection started in March until April 2022.Considering the limited time and the target Gen Z, this survey collected the data from respondents aged 18 to 24.From a total of 162 respondents, 3.09% respondents are 18 years old, 2.47% respondents are 19 years old, 18.52% are 20 years old, 29.63% are 21 years old, 30.86% are 22 years old, 9.26% are 23 years old, and 6.17% are 24 years old.In conclusion, 162 respondents that participated in this survey are meet with the criteria of this research.One of the demographic variables gathered in this survey is the gender of the respondents.This study classifies the respondents' gender into two groups: male (22.22%) and female (77.78%).
The occupation of respondents is also become one of the demographic information collected in this study.This study categorizes respondents' occupations into five groups: student, entrepreneur, employee, freelancer, and others, with 83.95% of the respondents are students, 1.23% are entrepreneurs, 12.35% are employees, 1.85% are freelancer, and 0.62% of them are categorize as unemployed.Based on this data, it can be assumed that the respondents' occupations vary, with most of them are students.
In this study, domicile also becomes one of the important data of demographic profile section since it is one of the requirements criteria of this study.As stated in previous chapter, this study targeted participants from Gen Z who are currently living in Jakarta, Indonesia.This study classifies the respondents' domicile into five categories which are West Jakarta, Central Jakarta, South Jakarta, East Jakarta, and North Jakarta.Based on the results, 9.26% of the respondents are live in West Jakarta, 13.58% are live in Central Jakarta, 50% are live in South Jakarta, 14.20% are live in East Jakarta, and 12.96% are live in North Jakarta.By looking at these results, it shows that all of them are meet with the respondents' criteria for this study.In addition, we can conclude that the majority of the respondents in this study are those who live in South Jakarta.
The number of Instagram influencers followed by respondents is also one of the most essential parts in the exposure toward the Instagram influencers since it becomes one of the requirements of the respondents' criteria in this study.The study targets the Gen Z who have followed an Instagram influencer on his/her Instagram accounts.Hence, this study only focused on the respondents who have followed at least two Instagram influencers.This study classifies the number of Instagram influencers followed by respondents into five categories which are 2, 3, 4, 5, and more than 5. From a total of 162 respondents, all of them are follow the Instagram influencers on his/her accounts.10.49% of the respondents followed two Instagram influencers, 19.14% followed three Instagram influencers, 16.67% followed four Instagram influencers, 1.85% followed five Instagram influencers, and 51.85% followed more than five Instagram influencers.Based on this data, it shows that most respondents have followed more than five Instagram influencers on his/her Instagram accounts.
The intention of purchasing product/service reviewed by Instagram influencers also become one of the requirements of the respondents' criteria in this study.The study targets Gen Z who had purchase product/service reviewed by Instagram influencers.Therefore, the study only focused on the respondents who had purchased product/service reviewed by Instagram influencers at least once.This study classifies the intensity of purchasing product/service reviewed by Instagram influencers into six categories which are 1 time, 2 times, 3 times, 4 times, 5 times, and more than 5 times.From a total of 162 respondents, all of them had purchased a product/service reviewed by Instagram influencers.9.88% of the respondents had purchased product/service once, 29.01%had purchased two times, 25.93% had purchased three times, 12.96% had purchased four times, 1.85% had purchased five times, and 20.37% had purchased more than five times.Based on this data, it shows that most respondents had purchased a product/service reviewed by Instagram influencers two times.

Multiple Linear Regression
In Table 2, the results shows that the value of the Adjusted R² is 0.692.Additionally, the result also shows the value of the R² which is 0.698.It means that 69.8% of the dependent variable purchase intention can be explain by the independent variable, Instagram influencer's credibility, expertise, and trustworthiness.Nevertheless, the remaining 30.2% of variables are impacted by other factors which are not included in this study model.The R² of this research model is more than 50% which imply that the regression model of this study is perfectly good to explain the effect of Instagram influencer on customer purchase intention.

F Test
Based on Table 3, the results show the value of F-statistics and Significance.According to the table above, the result of F-statistics in this model is 121.757.The F-test is then performed using the first method, which is by comparing the F-test with the F-statistics.In the F-table, there are two component of F-statistic value which are the df1 as the numerator and df2 as the denominator.The numerator of this study is 3 which is the number of the independent variable (k).While the denominator is the result of the number of gathered data (n) (162) subtracted by the number of independent variables (3) so the result will be 159 (162-3).From the information above, it can be found the value of F-statistic from the F-table which is 2.66.Additionally, it can observe that the value of F-statistics is greater than the F-table (121.757> 2.66).Thus, the null hypothesis of this study should be rejected.Furthermore, the results of the ρ-value (0.000) in this model also less than the significant level of 0.05, which strengthen the decision to reject the null hypothesis of this study.

T test
Based on Table 4, the result shows the t-statistics and the p value (Sig.) of Instagram influencer's credibility.The value of t-statistics is compared to the t-table.The value of t-table is determined by the degree of freedom.The degree of freedom is calculated by subtracting the number of gathered data (162) with the total number of independent variables (3) and subtract by 1.Hence, the degree of freedom of this study is 158 (162-3-1).Based on the results, the t-table value of this study is 1.975.Based on Table 4, the value of t-statistics of X1 is 1.636 which is less than the value of T-table of 1.975.By looking at this condition, the null hypothesis is accepted.In addition, the p value of X1 is 0.104 which is greater than 0.05.Therefore, the null hypothesis is not rejected which indicates that X1 or Instagram influencer's credibility is not significant to affect customer purchase intention.Based on Table 4, the result shows the t-statistics and the p value (Sig.) of Instagram influencer's credibility.The value of t-statistics is compared to the t-table.The value of t-table is determined by the degree of freedom.The degree of freedom is calculated by subtracting the number of gathered data (162) with the total number of independent variables (3) and subtract by 1.Hence, the degree of freedom of this study is 158 (162-3-1).Based on the results, the t-table value of this study is 1.975.Table 4 shows that the value of t-statistics of X2 is 4.353 which is greater than the value of T-table of 1.975.By looking at this condition, the null hypothesis rejected.In addition, the p value of X2 is 0.000 which is less than 0.05.Therefore, the null hypothesis is rejected which indicates that X2 or Instagram influencer's expertise is significant to affect customer purchase intention.In addition, the coefficient of X2 is positive, which implies that X2 has positive significant.
Based on Table 4, the result shows the t-statistics and the p value (Sig.) of Instagram influencer's credibility.The value of t-statistics is compared to the t-table.The value of t-table is determined by the degree of freedom.The degree of freedom is calculated by subtracting the number of gathered data (162) with the total number of independent variables (3) and subtract by 1.Hence, the degree of freedom of this study is 158 (162-3-1).Based on the results, the t-table value of this study is 1.975.Based on Table 4, the value of t-statistics of X3 is 6.902 which is greater than the value of t-table of 1.975.By looking at this condition, the null hypothesis rejected.In addition, the p value of X3 is 0.000 which is less than 0.05.Therefore, the null hypothesis is rejected which indicates that X3 or Instagram influencer's trustworthiness is significant to affect purchase intention.In addition, the coefficient of X3 is positive, which implies that X3 has positive significant.

V. CONCLUSION
The main objective of this research is to examine the effect of Instagram influencers' credibility, expertise, and trustworthiness on customer purchase intention for Gen Z in Jakarta, Indonesia.The study's independent variable is the Instagram influencer's credibility, expertise, and trustworthiness, while purchase intention is the dependent variable.Several statistical analyses were performed to identify whether or not the Instagram influencer's credibility, expertise, and trustworthiness is a significant factor in determining customer purchase intention.
The first objective of this study is to identify the effects of Instagram influencers' credibility on Gen Z's purchase intention.Based on the result of the t-test, the results indicate that there is no significant relationship between Instagram influencers' credibility and customer purchase intention.The second objective of this study is to identify the effects of Instagram influencers' expertise on customer purchase intention.Based on the result of the t-test, the results indicate that there is a significant positive relationship between Instagram influencer's expertise and customer purchase intention.The third objective of this study is to identify the effects of Instagram influencers' trustworthiness on customer purchase intention.Based on the t-test, the results indicate that there is a significant positive relationship between Instagram influencers' trustworthiness and customer purchase intention.Based on the result of statistical analysis in this study, it can be concluded that Instagram influencer's expertise and trustworthiness are significant factors in determining customer purchase intention.
According to the statistical analysis findings conducted in this study, Instagram influencers' expertise and trustworthiness are significant positive factors affecting customer purchase intention.An Instagram influencer's trustworthiness has been shown to have the most significant impact on purchase intention, followed by an Instagram influencer's expertise.These findings are not aligned with the previous study conducted by Kemeç and Yüksel (2021), in which the study found that influencer's credibility had significantly and positively affected purchase intention.However, the findings of this study imply that there are only two factors that are significantly affected the customer purchase intention, which is Instagram influencer's expertise and Instagram influencer's trustworthiness.

Theoretical Implications
The finding that Instagram influencers' expertise has a significant impact on purchase intention aligns with the research conducted by Botelho (2019).The result of the study indicates that social media influencers' expertise affects the individual's purchase intention.In addition, the positive significance of Instagram influencers' trustworthiness towards customer purchase intention is present in this study.However, this finding is not aligned with the research conducted by Botelho (2019), in which the result of the study shows that an influencer's trustworthiness does not affect the purchase intention.According to Pornpitakpan & Francis (2008), the discrepancies in the findings may be attributed to the difference in cultural values.Indonesian people, specifically in Jakarta, who were become the respondents in this study, tend to be very concerned about Instagram influencer's expertise and trustworthiness than do American respondents in Ohanian (1991) and the respondent in the study conducted by Botelho (2019, which only expertise was a significant factor affecting purchase intention.

Managerial Implications
This study brought valuable findings for entrepreneurs, marketers, and academics in marketing.The findings provided a better understanding of how Instagram influencers affect customer purchase intention and what are the characteristics most valued by customers, especially for Gen Z in Jakarta, Indonesia.Entrepreneurs and marketers can better select Instagram influencers to collaborate with, academics have more insight into Instagram influencer marketing, and Instagram influencers can know what to focus on if they want to have a more significant impact on customer purchase intention.
According to the research findings, Instagram influencers' expertise and trustworthiness positively affect purchase intention.As a result, the marketer, entrepreneur, and Instagram influencers need to focus on these elements to increase customer purchase intention.The research suggests that to increase customer purchase intention, they need to pay attention to several factors such as knowledgeable, expert, and skilled as the indicator to determine Instagram influencer's expertise.In addition, marketers need to consider collaborating with Instagram influencers since the results show that customers prefer ads and tend to buy a product/service promoted by Instagram influencers who are experts in their fields.Not only that, sincere, trustworthy, dependable, and reliable are the other factors that should also be considered to examine Instagram influencers' trustworthiness.Since Instagram influencers have succeeded in encouraging customers to believe in every product/service they reviewed, it will increase Instagram influencers' trustworthiness and customer purchase intention.These findings can be used as a basis for decision making by companies, marketers, or entrepreneurs as well as material for future research because statistical evidence has shown that Instagram influencers' expertise and trustworthiness are significant factors influencing customer purchase intention.In conclusion, if a marketers/advertisers want to collaborate with an Instagram influencer, they need to choose an Instagram influencer who is perceived to be knowledgeable, expert, skilled with respect to the product being promoted, and who are perceived to be sincere, dependable, reliable, and trustworthy.

Limitations and Future Research
This study aims to analyze the effect of Instagram influencers on customer purchase intention for Gen Z in Jakarta, Indonesia.Thus, it is suggested to observe other cities for future research.It would be interesting since people have different backgrounds, cultures, preferences, and purposes in using Instagram and perceptions about Instagram influencers.Therefore, it will be insightful to conduct the research in other cities that may have different characteristics and demographic profiles as well as purchase behavior.Not only that, but it is also interesting if, in the future, there is a study that could expand the target respondents to include Generation X or the Millennials.
The limitation of this study is that it only focused on Instagram influencer as the object of study.Therefore, future research is suggested to analyze other influencers on other social media platforms such as YouTube and TikTok.Future studies could have different results and insights by exploring other social media platforms since each social media platform will have a unique marketing and advertising approach.Furthermore, this study also suggested that future research add more variables to clearly explained the customer purchase intention.

Figure 1 .
Figure 1.Proposed Framework Model (a) Respondents are currently using Instagram in their daily activity, (b) Respondents are Gen Z aged 18-24, (c) Respondents are living in Jakarta, Indonesia, (d) Respondents already follow at least two Instagram influencers, and (e) Respondents have purchased a product or service on Instagram at least once.

Table 1 .
Validity and Reliability Tests