INTRODUCTION

The changes, complexities, and dynamics created in various systems of the present era have led the practices and strategies that were used in the past to administrate organizations lose their efficiency, and the organizations that still insist on using their traditional methods are doomed to failure and destruction [1]. In the current era, environmental conditions have become so complex and ambiguous that the organizations can no longer solve their managerial and administrative problems by the traditional approaches and practices; therefore, the current organizations by understanding the changes in management structure and methods, while removing current management and administration issues and problems, should also be able to guarantee their long-term survival [2]. The majority of organizations have theoretically accepted that they either should change or end their activity. In fact, the changes and complexities of the working environment compel organizations to increase their capabilities to respond to the environmental changes.

On the other hand, organizations are established and organized according to different goals and strategies and in various forms [3]. Organizational structure has the most important role in achieving a successful strategy, and on the one hand, is one of the important factors in knowledge management [4]. The information that organizations acquire over time is very important, and organizational success is highly dependent on the use of organizational knowledge in the organizational structure [5]. Regarding the importance and role of structure in the effective function of the organizations, it is an essential issue to determine what the structure of the organization should be. The structure of the organization plays the most important role in the effective function of today's organizations from small repair workshops to national governments. The structure of an organization is considered as a set of paths in which the activities of the organization are divided into known duties, and coordination is created among these duties. By entering the knowledge and wisdom era, the importance of knowledge, knowledge management and so on in the organization is increasing day by day and this factor has a close relationship with the organizational structure [6].

Organizational structure influences the performance improvement of the organization and organizational structure characteristics influence the process of knowledge management deployment and its retention. On the other hand, one of the barriers to develop organization and entrepreneurship at the organizational level is the incompatibility of organizational structure with entrepreneurship development and organizational responsibilities. According to the stated points, one of the basic problems of efficiency and effectiveness of organizations, especially government organizations, is the issues related to their organizational structure. Structure designing is considered as one of the critical responsibilities of management and can lead the organization towards success or failure depending on how it is implemented and formed [7]. Considering that many existing structures are traditional, it is necessary to evaluate the existing organizational structures at various times and the organization should be investigated according to the content goals and dimensions.

The Welfare Organization is constantly undergoing changes and shifts among various ministries, and on the other hand, the structure of its deputy of rehabilitation is constantly changing, in a way that in the last few years constant changes have been performed in its various offices, which it is necessary to design the structure model of the deputy of rehabilitation to reach relative stability in the structure to provide desirable service to the target community so that both resources depletion and the job burnout of working human forces are prevented. To the best of our knowledge, so far no study has been performed to design an optimal model of organizational structure for the deputy of rehabilitation of the Welfare Organization. Therefore, due to the importance of organizational structure, this study has been conducted to design an optimal model of the organizational structure for the deputy of rehabilitation of the Welfare Organization in Iran.

Theoretical Foundations

Organizational Structure

Kia defined structure before defining organizational structure. According to him, the model of connections and communications of the components of each system is called the structure of that system. From his point of view, duplicate communications that are regularly and orderly performed create the structure of the organization [8]. The structure of the organization stipulates how duties are assigned, who should report to whom, and what are the formal coordination mechanisms and also what are the interactive organizational models that must be observed [9]. Organizational structure is a relatively fixed framework of jobs and units that influences the behavior of individuals and groups toward organizational goals. Robbins defined organizational structure in the book "Foundations of Organizational Behavior" as: organizational structure formally specifies how to classify, create group, and coordinate duties [10]. According to Blau and Schoenherr, the organizational structure is defined as: employing and appointing people at various locations of the chart of organization and in organizational positions that affect the organizational relationships of these people [11].

Precision in defining organizational structure refers to three main elements [12]:

1. Organizational structure determines the formal relationships of reporting within the organization and shows the levels existing in the administrative hierarchy and also specifies the control domain of the managers or supervisors.
2. Organizational structure determines those who work as a group in administrations or grouping and classifying administrations that exist throughout the organization.
3. Organizational structure includes the design of systems by which the activities of all administrations are coordinated and integrated, and thus the effective communication system (organization) will be guaranteed.

Organizational structure is influenced by the goals, strategy, environment, technology, and size of the organization. These are the main factors that represent the position of the organization, and an effective relationship is created between the organization and the environment. Content variables represent the organization and environment in which the structural variables are embedded. Structural factors represent the internal characteristics of an organization and the organization can be evaluated by them. Content variables affect the structural variables. Complexity, formality, and concentration are the most important structural variables.

Investigating Structural Dimensions

Structural dimensions of an organization represent the intrinsic characteristics of an organization that include three dimensions of complexity, formality, and concentration, that the intensity or weakness of each of these dimensions affects the efficiency and effectiveness of the organization.

1. Complexity: Complexity refers to the ratio of specialization, work division, and the number of levels in the hierarchy of the organization and also explains the boundary that organizational units are geographically dispersed. In other words, complexity is the degree of specializing individuals according to the occupational expertise within the organization and can be defined and measured by the number of places where work is done, the number of jobs performed, and the number of hierarchies that perform various duties [13].
2. Formality: The extent to which an organization relies on laws, regulations, and procedures to direct its employees' behavior is called formality. In a formal organization, organizational relationships are described in writing, precisely and according to the organizational chart for the employees, and if necessary, subsequent changes are formally announced by the manager, but in an informal organization, organizational relationships are verbally expressed for the employees and, if necessary, are normally changed [14].
3. Concentration: Concentration refers to the location of taking the organization's decisions. The more limited the power of decision making and the scope of authority are and decisions are made at the top of the organization, to the same ratio the organization will be more centralized. This means that limiting the right of the freedom of action of low-level employees of the organization in their decision-making and their adherence to the rules and policies has been established [15].

In a research using the informal structure as the key dimension, Monavarian et al. [16] described the distinctive structural dimensions of the knowledge-based organizations such as informal relationships, trust-oriented relationships, inclusive emotional relationships, and extroverted interactive relationships, and afterward investigated the characteristics of important content dimensions of the knowledge-based organizations, that are environment, technology, and culture. Keshvari [17] determined the informal structure as an important structural aspect and emphasized three new dimensions of this structure, namely trust-based relationship, interactive relationship inside and outside the organization, and inclusive emotional relationship. Monavarian and Asgari [18] presented a research entitled "The Development of Structural Dimensions of the Organization in Accordance with the Knowledge Management Approach". The results of applying statistical analysis methods showed that the structural components of formality and concentration have a negative impact on knowledge management measures.

Investigating the Content Dimensions

The content dimensions of an organization are in four dimensions of the lack of environmental certainty, strategy, organizational culture, and technology that represent the organization and its position.

1. Environment: The environment refers to all factors that exist outside the organization's boundary and have direct impacts on the organization. The capability to predict the environment has a direct impact on the ability of the organization to perform duties. If the environment is unpredictable and rapidly changing, the organization must have a flexible and responsive structure and should have the ability to adapt to environmental changes [19].
2. Strategy: Strategy means actions that the organization plans to respond to or anticipate environmental changes. Indeed, strategy determines how an organization achieves its goals [14].
3. Organizational Culture: Culture is the planning of the mind that distinguishes the members of one organization from another organization. Organizational change is not successful regardless of the role of organizational culture. In a way that one of the main reasons for the failure of organizational changes is to ignore organizational culture [20].
4. Technology: Technology is the process of production and includes machinery, practices, procedures, and methods of doing affairs (2). Nowadays, advanced information technologies enable managers to communicate better and more with the organization and the environment. Using information technology, the ratio of authorities of the employees can be enhanced, and complete information can be given to them so that they can perform their job or duty in a perfect way [1].

Yusefi et al. [21], in a research, showed that if the hospitals under study follow an analytical strategy, they should reduce the ratio of their complexity and concentration and have tight control over current activities and have limited control over new activities. Shukr and Ramli [22] demonstrated that incentives composed of responsibility, honesty, accountability, and transparency can be exploited to evaluate performance. This article while adding knowledge to the available limited texts about balanced scorecards improved the issues related to quality improvement and patient satisfaction in the Malaysian health care sector. Cristobal et al. [23] stated that based on organizational culture, the size of the organization as well as the size of the project and the organizational structure are localized and optimized.

MATERIALS AND METHODS

The present research is considered among field researches in which the researcher has collected the required primary data in the form of a questionnaire and interview. Since the present research is considered among the combined researches, consequently quantitative and qualitative research strategies are also used to perform it. This research used combined exploratory methods -typology creation model- as a research strategy. Combined methods focus on collecting, analyzing, and combining qualitative and quantitative data simultaneously in a single study or a set of studies. Library studies, interviews, and questionnaire were for data collection.

This research was conducted in three stages. In the first stage, which was performed qualitatively, the data was collected through structured interviews with rehabilitation authorities, managers, and experts. In the second stage, key themes were extracted and converted to the corresponding model. In the final stage, the extracted model was tested, and this stage was performed quantitatively.

The first stage of this research was conducted qualitatively; the research strategy used in this stage was fundamental data theory. Having specified the factors affecting the optimal model of organizational structure, the questionnaire was arranged to survey the experts involved in everyday issues in this field and the research variables were investigated. The Delphi method was used to investigate the factors. Finally, information processing and the analysis of the Delphi open questionnaire were carried out and based on the obtained data and results, the proposed research model concerning the determination of the factors affecting the organizational structure optimization of the deputy of rehabilitation was compiled. The structural equations method was used to investigate the model.

In the present research, a non-random sampling method of the selective type of the purposeful sampling method (snowball), the theoretical saturation criterion, and the key sample technique (experts) were used. The population consisted of the managers and experts of the deputy of rehabilitation, and the available sampling method was used. The statistical population was equal to 4,000 persons. The sample size was 370 people according to Morgan's table, and after several stages of collecting questionnaires, 300 questionnaires were collected.

RESULTS AND DISCUSSION

In this research, all interviews were entered into MAXQDA software for open coding. Necessary investigations were performed and the desired codes were extracted. The code was labeled based on the performed interviews, and the researcher tried to adhere to the individuals' insight about the given response to the necessary extent to avoid any possible unintended and probable bias as much as possible. During axial coding, the categories extracted from open coding were located into 6 categories including axial category, causal conditions, intervening conditions, contextual conditions, strategies, and consequences. According to the presented descriptions and explaining the components of the axial coding model in the MAXQDA software, the model of structure improvement of the deputy of rehabilitation was designed as follows (Figure 1).

In this research, the Kolmogorov-Smirnov test was used to test the data normality. The test results of the data normality are presented in Table 1.

According to the results of Kolmogorov-Smirnov test, in all cases the significance value was higher than the error level (0.05). So the data distribution was normal.

Confirmatory Factor Analysis of the Causal Conditions Scale

The results of the factor analysis of the causal conditions variable scale are presented in Figure 2. This scale contains 3 hidden variables and 21 observable variables. The observed factor load in all cases has a value higher than 0.3, indicating that the correlation between the hidden variables (dimensions of each one of the main constructs) and the observable variables is acceptable. Having identified the correlation of the variables, the significance test should be performed. The t-value statistic is used to investigate the significance of the relationship between variables. Since the significance is investigated at the 0.05 error level, so the relationship is significant if the t-value statistic test is higher than the critical value of 1.96. Based on the results of the measurement indices of each of the scales used at 5% confidence level, the t-value statistic is higher than 1.96, indicating that the observed correlations are significant.

All factor loads are higher than 0.3. To express the model's acceptability, Bentler-Bonett normalized fit indices, relative fit, incremental fit, comparative indices, and complete squares were used (Table 2).

The obtained RMSEA value was 0.011 that according to the standard value of less than 0.1 was desirable.

Confirmatory Factor Analysis of the Contextual Conditions Scale

The results of the factor analysis of the contextual conditions variable scale are presented in Figure 4. This scale contains 1 hidden variable and 9 observable variables. The observed factor load in all cases had a value higher than 0.3, indicating that the correlation between the hidden variables (dimensions of each one of the main constructs) and the observable variables was acceptable. Since the significance was investigated at the 0.05 error level, so the relationship was significant, if the t-value statistic test was higher than the critical value of 1.96. Based on the results of the measurement indices of each of the scales used at 5% confidence level, the t-value statistic was higher than 1.96, indicating that the observed correlations were significant.

All factor loads were higher than 0.3. To express the model's acceptability, Bentler-Bonett normalized fit indices, relative fit, incremental fit, comparative indices, and complete squares were used (Table 3).

Confirmatory Factor Analysis of the Intervening Conditions Variable Scale

The results of the factor analysis of the intervening conditions variable scale are presented in Figure 6. This scale contains 1 hidden variable and 6 observable variables. The observed factor load in all cases had a value higher than 0.3, indicating that the correlation between the hidden variables (dimensions of each one of the main constructs) and the observable variables was acceptable. Based on the results of the measurement indices of each of the scales used at 5% confidence level, the t-value statistic was higher than 1.96, indicating that the observed correlations were significant.

All factor loads were higher than 0.3. To express the model's acceptability, normalized fit indices were used (Table 4).

Confirmatory Factor Analysis of the Strategies Scale

The results of the factor analysis of the strategies factors variable scale were presented in Figure 8. This scale contains 1 hidden variable and 10 observable variables. The observed factor load in all cases had a value higher than 0.3, indicating that the correlation between the hidden variables (dimensions of each one of the main constructs) and the observable variables was acceptable. Based on the results of the measurement indices of each of the scales used at 5% confidence level, the t-value statistic was higher than 1.96, indicating that the observed correlations were significant.

All factor loads were higher than 0.3. To express the model's acceptability, normalized fit indices were used (Table 5).

Confirmatory Factor Analysis of the Consequences Scale

The results of the factor analysis of the scale of the consequences are presented in Figure 10. This scale contains 3 hidden variables and 7 observable variables. The observed factor load in all cases had a value higher than 0.3, indicating that the correlation between the hidden variables (dimensions of each one of the main constructs) and the observable variables was acceptable. Based on the results of the measurement indices of each of the scales used at 5% confidence level, the t-value statistic was higher than 1.96, indicating that the observed correlations were significant.

All factor loads were higher than 0.3. To express the model's acceptability, normalized fit indices were used, and the obtained results of the model are shown in Table 6.

Designing Structural Equations

After confirming the factor structure of research structures, structural equation modeling was used to investigate the relationships between variables. Structural equations were used to assess research hypotheses.

All factor loads were higher than 0.3. To express the model's acceptability, Bentler-Bonett normalized fit indices, relative fit, incremental fit, comparative indices, and complete squares were used, and the obtained results of the model are shown in Table 7.

The obtained RMSEA value was 0.026 which according to the standard value of less than 0.1 was desirable. The ratio of chi-square to the degree of freedom was equal to 2.491 and was desirable. In general, concerning all indicators, it can be said that the model had a good fit. Factor loads indicate the impact ratio of the observed variable in explaining and measuring hidden variables related to it. The significance level confirmed the factor load.

In the following, the impact of identified factors on each other was investigated.

According to the table, the factors identified in the foundation data model was influential on each other. The factor load of causal factors on the main category was 0.71, and its t-statistic was 5.67. The factor load of contextual factors on strategies was 0.52, and its t-statistic was 3.61. The factor load of intervening factors on the strategies was 0.44, and its t-statistic was 2.59. The factor load of the main category on the strategies was 0.68, and its t-statistic was 4.7. Finally, the factor load of the strategies on the consequences was 0.69, and its t-statistic was 8.24. So. It can be said that the research model is confirmed.

CONCLUSION

Based on the conducted interviews and investigating previous studies, the factors that affect designing the optimal model of organizational structure for the deputy of rehabilitation of Iran's Welfare Organization were identified. These codes were evaluated and screened using the Delphi technique and confirmed after three Delphi rounds. Using confirmatory factor analysis technique, the components of the organizational structure were evaluated and ranked in the Foundation Data Model and finally evaluated and analyzed based on the Structural Equations Model of the Organizational Structure Foundation Data Model of the Deputy of Rehabilitation. The results of the analysis are presented in the following table.

Based on the foundations and the steps of foundation data theory, a desirable model was presented. The basis of the general management model, strategic management, is a process in which strategic planning is performed, and a complete plan is presented for the implementation of strategies and also controlling and evaluating them. Strategic management has three main stages that in the first stage the strategic plan is compiled, in the second stage the necessary context for implementing the strategies is provided (strategic implementation) and in the third stage the accuracy and credibility of the program and strategic implementation are controlled. Determining the strategic issues of the organization's advancement is the heart of the strategic planning process. Strategic issues are strategic, major and fundamental decisions that affect strategic goals, strategies, and sub-strategies. The purpose of this stage is to determine the strategic goals and strategies that the organization needs them fundamentally.