Introduction

The globalization process and technological progress affected by the augmenting competition alongside the giant leap in the increasing demands of customers have led organizations to imbibe the volatility and ambiguity of the environment (Bagheri, Shahpar, Zarifi, & Deldar, 2017). The tough competition has stimulated most organizations to improve their customer service via marketing tools to gain a competitive edge to give customer satisfaction and loyalty momentum (Gounaris, 2008). Additionally, marketing tools cannot be considered a means to meet customer needs, and the organizations should satisfy the needs of other stakeholders. The employee should be considered the significant members of the stakeholders who have an undeniable influence on the customers to comprehend the organization's value directly and indirectly. Therefore, improving the process of value proposition could be accelerated by satisfying the employee (Gounaris, Vassilikopoulou, & Chatzipanagiotou, 2010). The significance of human resources in the prosperity of organizations has been revealed in academic research, and plenty of research has been conducted enriching the literature of Internal Marketing. Through Internal Marketing literature, the employee has been deemed an Internal Customer of the organization (Balemba, Deogratias, & Akonkwa, 2016). In other words, the employee is considered the organization's internal market. Not until the organizations meet the employee's expectations could they give services to the customers that are commensurate with their expectations (Hosseinee & Rahmani, 2012). Remarkable achievements could be obtained by establishing Internal Marketing strategies deepening the employee's knowledge and skills, which would result in improving their incentives and performance (Balemba et al., 2016).

Through past studies, multiple factors have been discovered as the consequences of Internal Marketing. Regarding the variety of the distinguished consequences, more research is required. For example, organization Commitment (Kafashpour, Rahimnia, & Ibrahim, 2017) (Ebrahimi, Mohammadi, & Shoja, 2018), Citizenship Organization Behavior (Abdolahi & Ghoujali, 2017) (Esmaeilpour & Tavana, 2017), Organization Innovation (Imani, Gaskari, & Gheitani, 2015) (Mirkazemi & Kavosybijar, 2017), and Organization Performance have been revealed as the consequences of Internal Marketing in the past studies. Conducting further research would contribute to acquiring more relevant and practical results through the meta-analysis of the previous findings. In the previous studies, a sequential relationship has been found between the consequences of Internal Marketing. Therefore, an Interpretive Structural Modeling has been utilized to distinguish the sequential relationships of the Consequences of Internal Marketing in the current study. To elucidate it, Interpretive Structural Modelling is a method for analyzing the impact of a factor on other factors and the relationship between them. The hierarchy and the direction of the factors in complicated models can be calculated through this method.

In general, two main questions are going to be answered in this study:

1. What are the main consequences of Internal Marketing revealed in the previous studies in Iran? What is the priority?
2. What are the cause-and-effect relationships among the consequences of Internal Marketing in Kharazmi University?

In order to answer the mentioned questions, the consequences of Internal Marketing would be discovered with the meta-analysis method; moreover, the cause-and-effect relationships could be distinguished through Interpretive Structural Modeling.

Literature Review

The concept of Internal Marketing was introduced by Berry in 1980. The employee is considered as the internal market of the organization. To delve more into it, fulfilling the needs of the members of the internal market of every organization is essential for the prosperity of that organization. Therefore, human resources and intangible assets are vital perquisites for value creation (Kaplan & Norton, 2011). As a matter of fact, human resource is a sustainable competitive advantage meeting the needs of those who are essential for preserving the organization and giving high-quality service to customers. Therefore, the employee is considered the most valuable asset, leading the organization to acquire a sustainable competitive advantage (Doukakis, 2002).

Defined by Kotler, Internal Marketing is defined as the process of tutorial and motivation of the employee to improve their performance in giving service to customers. According to the research done by Berry and Parasuraman, proposing the employee as internal customers and their occupations as internal products are the principles of Internal Marketing. Subsequently, the customers' demands would be satisfied (Mosahab, Mahamad, & Ramayah, 2010). Furthermore, Internal Marketing is a scheduled strategy concentrating on Marketing principles to vanquish the resistance to change, stimulation, and integration to increase the effectiveness in all levels of the organization, which may lead to augmenting incentives. Utilizing marketing strategies to intrigue the employee would contribute to obtaining better performance compared to utilizing traditional human resource management strategies (Anoskie, 2008).

In general, components of Internal Marketing are defined as employee safety, extensive tutorials, remarkable rewards based on performance, information sharing, empowering the employee, and eliminating the discriminations according to the research conducted by Bensal et al. (Bansal, Mendelson, & Sharma, 2001). Additionally, components of Internal Marketing that have been defined by Foreman and Money include:

• Vision: the desired future of an organization illuminating the direction of the activities in the long term is defined by vision. Defining this vision is one of the principal responsibilities of leaders. In other words, it is one of the principles of Strategic Planning. If an appropriate and attractive vision were designed by a leader, the employee would become more inclined to accomplish that vision's objectives. In other words, vision is such a bridge linking the present to the future.
• Development:  Prosperity, tackling the weaknesses, and productive teamwork would be achievable by empowering the employee. The eventual objectives of any organization would be driven by the employee stimulation acquired by empowering their skills. Additionally, employee empowerment can result in a positive attitude toward the job and job evaluation, stimulation, better service quality, and increased efficiency.
• Reward: Reward is given to the employee because they endeavor to achieve the organization's objectives, devoting energy and creativity to obtain more efficient procedures. If the performance standard is higher than regular performance, it is considered a special reward; otherwise, it is a salary (Karimi, Shokouhi, Shabani, & Gilani, 2016).

Research Method

The research is a descriptive and practical study, and due to the meta-analysis method, it is defined as a quantitative study. Meta-analysis is a statistical method to combine the results of a series of independent research related to a particular subject. The statistical population of meta-analysis research consists of the previous studies. Meta-analysis is conducted on qualitative studies (Pigott, 2012). Measuring the size of the effect is the principal of the Meta-analysis. That is the ratio of the significance test to the size of the research. The size of the effect indicates the degree of the presence of a phenomenon in the population. The bigger the size of the effect, the higher the degree of the presence of a phenomenon.

The factor of the size of the effect (r) is obtainable by sample statistics such as t, x², and F. The sizes of the effects that are less than 0.3, between 0.3 and 0.5, and more than 0.5 are considered low, medium, and high, respectively. Although the significance test and the effect size are utilized to accept or reject the zero hypotheses, each indicator is endowed with different information. The significance test is utilized to distinguish whether a specific result has been obtained by chance or whether the dependent variable is affected by the independent variable. Consequently, the result of the effect size alongside the significance test is essential to decide whether to accept or reject a zero hypothesis. In equal terms, regarding the significance ratio and size of the sample, the bigger the effect size, the more accurate the test and result (Ghorbanizadeh, 2015). The published papers in Persian journals and the theses of master's degrees done between 2010 and 2019 in Iran are chosen as the statistical population of the research. The previous studies with the data standards are selected as the research sample, and the sampling method is goal-oriented. The standards of the data include 1. The study should have investigated the consequences of the Internal Marketing 2. The study should have endowed the cardinal information to calculate the effect size (the strength of relationship). The sample size of this study includes the meta-analysis of 51 cases equal to 78 units of meta-analysis. Table 1 Includes the factors considered for choosing studies for meta-analysis.

Table 1: choosing previous studies for meta-analysis

CMA2 software (meta-analysis software) is utilized to analyze the chosen papers. In addition, the funnel test is used to measure bias, Dual and tweed fitting is used to modify bias, and Fail-Safe N is utilized to address the lost studies. Finally, the Cochran test is used to evaluate the divergence of the studies. The general information of the selected studies is indicated in Table 2.

Table 2: the general information of the selected studies

In the second step, Interpretive Structural Modelling is used. Interpretive Structural Modelling is a method for distinguishing the relationships among the components of a system, and it is an interactional understanding of integrating the components in a comprehensive system. This method is established based on mathematics and Graph, social sciences, and group decision-making, which gives discipline to the components of the system. This method helps to discern the inter-relationships and measure the variables' effects on the others (Malekzadeh, Ekramifard, & Malekzdeh, 2017). Regarding the purpose of this study, the questionnaire is the data gathering tool in Kharazmi University given to the experts. The study's statistical population is the faculty of Kharazmi University with a goal-oriented sampling method. The Content Validity method is used for evaluating the validity of the study. The questionnaire was confirmed by some professors at the university. Judgmental Purposive Sampling is used in this study, and 12 professors have reached a consensus on the issue. The intraclass Correlation Coefficient (ICC) method is also used to confirm the reliability. The index of ICC is 0.83, indicating strong reliability. The steps of Interpretive Structural Modeling include:

1. Discovering the factors affecting the system
2. Creating Structural Self-Interaction Matrix
3. Creating the initial Reachability Matrix
4. Creating the final Reachability Matrix and the output and input sets
5. Calculating the level of the variables
6. Designing the Interpretive Structural Model

Results

The Effect of Internal Marketing on 28 variables of previous studies, the frequency, frequency ratio, effect size, and significance level are illustrated in Table3. Among the Consequences of Internal Marketing, the Organization Commitment (16 studies), Job Satisfaction (8 studies), Organization Citizenship Behavior (8 studies), Customer-Oriented Approach (5 studies), Organization Performance (5 studies), Entrepreneurship Approach (5 studies), and Organization Innovation (5 studies) have the frequency in previous studies respectively.

Table 3: The size effect of the consequences of the Internal Marketing

According to Table 3, among the Consequences of Internal Marketing, Job Motivation (0.83), Knowledge Management (0.724), Organization Reputation (0.679), Employee Performance (0.666), Goal-oriented Approach (0.631), and Organization Productivity (0.588) have the most Size of Effect respectively. The frequency distributions of the effect size categories of the Consequences of Internal Marketing are indicated in Table 4.

Table 4: The frequency distributions of the size of effect categories of the Consequences of Internal Marketing

According to Table 4, among 28 variables, seven variables equal to 25% are categorized as low, 15 variables equal to 53.6% are categorized as a medium, and six variables equal to 21.4% are considered high. Evaluation of the Publication Bias is one of the significant issues in meta-analysis. When all studies on a specific subject are not analyzed by meta-analysis, Publication Bias occurs. Some studies may not have been published or indexed in journals for several reasons. A two-dimensional frequency chart named Funnel Chart is utilized to distinguish the Publication Bias. Additionally, the measured Interference Effect is drawn in front of each study's sample size. The Funnel chart of the study is illustrated in Figure 1.

Figure 1: Funnel Chart on the study

According to the descriptive attribute of the Funnel chart, studies with low standard error congregated above the funnel are free from Publication bias. The more the studies are below the chart, their standard error increase and the Publication Bias augments. Regarding Figure 1, there are some Publication Bias in the studies indicating that some of the studies have not been published or are not accessible. The Dual and tweed fitting and correcting method modifies the Publication Effect. A repetitive process is utilized to omit the inconsistent observations from the Funnel chart (deletion of redundancy from distribution)., the values dedicated to the lost studies are added. The Dual and tweed fitting and correcting method results are indicated in Table 5.

Table 5: Dual and tweed fitting and correcting method results

Table 6: The results of the Fail-Safe N (number of incomplete safe) Classic method

According to Table 6, 93183 studies should be accumulated and analyzed to limit the P-value of the domains to less than 0.05. Furthermore, an error may occur in the final results of analyses if 93183 further studies are conducted, indicating concise and accurate results obtained from the study. According to the significance level (P-value) obtained from Fail-Safe N and Dual and tweed fitting, the Cochran test is considered to evaluate the consistency of the size of effects. The zero hypothesis indicates a lack of significance level, and there is a significant difference among the size of effects. The findings of the Cochran test are indicated in Table 7.

Table 7: The findings of the Cochran test

Regarding Table 8, the significance level is less than the error (5%) in the 95% confidence level. As a result, H0 is rejected, and H1 is accepted. There is significant difference and inconsistency among the size of effects. An initial Reachability Matrix is calculated based on the comments of 12 faculties of Kharazmi University. The next step is to draw an Interpretive Structural Model according to the Consequences of Internal Marketing. The initial Reachability Matrix is indicated in Table 8.

Table 8: The initial Reachability Matrix

After calculating the initial Reachability Matrix, the final Reachability Matrix is obtained, indicated in Table 9.

Table 9: The final Reachability Matrix

Figure 2. Interpretive Structural Modeling of the Consequences of Internal Marketing

Considering the levels of the Consequences and the final Reachability Matrix, the Interpretive Structural Model is drawn, which is indicated in Figure 2.

After drawing the Interpretive Structural Modeling of the Consequences of Internal Marketing in Kharazmi, Permeability-Dependency Matrix is calculated. Permeability-Dependency Matrix is indicated in Table 10.

Table 10: Permeability and Dependency Matrix

Discussion and Conclusion

In the present study, meta-analysis is utilized to investigate the several results of the studies on the Consequences of Internal Marketing. Considering the meta-analysis results, among the Consequences, Job Motivation has the most effect (0.830), which is consistent with (Ozgit & Melhem, 2019) (Akbari, Ebrahimpour, & Ebrahimi, 2015). Employees would be provided with a sense of support, dependency on the organization, and stimulated by implementing practical programs of Internal Marketing in the organizations. Knowledge Management has a Size of Effect of (0.724) and is consistent with the (Hume & Hume, 2015) (Naeiji, Panahifar, & Esfandiari, 2017) findings. The more the employee possess knowledge and expertise, the more they can create and implement knowledge in the organization. The knowledgeable and skillful employee would endow their information to others, improving the competencies of the organization. The more the employee have competencies, the more knowledge management would be facilitated in the organization. Organization Reputation has an effect of (0.679), and the result is consistent with the (Vasconcelos, 2008) (Esmaeilpour & Tavana, 2017) studies. Implementing the Internal Marketing practices would provide reputation to the organization, strengthening the employee commitment. This Commitment is derived from comparing the organization's competencies with other weaker organizations. Considering the research findings, the Employee Performance has a size of the effect of (0.666), and the result is consistent with the findings of the (Mieres, Sánchez, & Vijande, 2012) (Izadi, Benesbordi, & Moeinfard, 2018) studies. Employee Performance is strengthened by employee stimulation to sharpen their skills. The practices of Internal Marketing empower this process by supporting the employee. The Goal-oriented Approach has a Size Effect of (0.631), and the finding is consistent with the findings of (Heper, Yolacan, & Kocaeksi, 2014) (Zare & Bagheri, 2017).

Regarding the Targeting Theory, in addition to the satisfaction of essential needs of people, the environment has a noticeable impact on targeting and motivation toward goals. A goal-oriented Approach would gain momentum by improving the Internal Marketing level in organizations. Market-oriented Approach is one of the Consequences of Internal Marketing with a size of the effect of (0.499), and this result is consistent with (Kyriazopoulos, Yannacopoulos, Spyridakos, Siskos, & Grigoroudi, 2007) (Hasangholipor, Ansari, & Elahi, 2012). Furthermore, Internal Marketing has a significant impact on Market-orientation. Market-oriented organizations can acquire market share and profit than organizations that pay scant attention to the market. In effect, the fundamental needs of customers and market trends can be addressed by market-oriented organizations more efficiently compared to other competitors. Job Satisfaction has a size of the effect of (0.484), and it is consistent with the findings of (Liao, 2010) (Ebrahimi et al., 2018).

Engaging the employee in decision-making processes, propagating efficient communications in the organization, and offering rewards that are considered as practices of Internal Marketing would increase Job Satisfaction. Considering the Interpretive Structural Modeling, three levels of Consequences of Internal Marketing in Kharazmi University have been discovered. Job Motivation and Goal-oriented Approach is categorized in the third level, which means that the variables mentioned earlier have the most effect on other variables and are affected the least by other variables. Employee Attitude toward the organizational atmosphere could be leveraged by implementing Internal Marketing practices, and then the Goal-oriented Approach would be entrenched in the organization. Deepening the knowledge and sharpening employee skills, Information endowment, and defining transparent vision would supplement the Goal-orientation in organizations that put their competencies into practice with solid stimulation. Knowledge Management and Employee Performance is categorized in the second level. One of the most indisputable perquisites for implementing Knowledge Management in organizations is Job Motivation. As a result, organizations should provide vital infrastructures and internal and external motivations for employees who contribute to value creation, sharing, and implementing knowledge in the workplace. Organization Productivity and Organization Reputation are categorized in the first level. In the final model, these variables have the most negligible impact on other variables and affect them the most. The following practices are suggested by evaluating the final model:

• Employees should be considered as the most valuable intangible asset. Therefore, job satisfaction, job security, and propagating efficient communication skills would play a cardinal role in strengthening job motivation and performance.
• Employee welfare should be considered as the most prominent issue. Providing tutorial programs and giving rewards should not be neglected. Putting Internal Marketing into practice would incur employees to work industriously along with the vision and mission of the organization.
• Organizational reputation should be given prominence by improving the organization's branding practices, employee competencies, and communications.

Although statistical issues such as sampling method and measurement error are corrected by the meta-analysis method with considerable accuracy, the present study was confronted with several limitations. First, the Publication bias would have occurred. However, the previous studies have been examined with accuracy, the probability of bias is not neglectable. Second, some critical variables would have been neglected to be considered as input of this research.
the following issues are suggested for further studies on this subject:

• Consequences with a size of the effect that is more than 0.5 could be examined practically in the organizations.
• The results acquired from this research have been measured quantitatively, which may not be comprehensive indicators of the real Consequences of Internal Marketing. Therefore, a qualitative study is suggested to be conducted to analyze the Consequences of Internal Marketing. Moreover, the results obtained from the qualitative method could be compared to the results of the present study, which would give a broad insight to the researchers.