Abstract
The purpose of the current research is to investigate the effective factors in hiding knowledge in the country's water and sewage engineering company. This research is in the basic research category in terms of purpose. The current research was conducted using the qualitative method and based on the phenomenological approach. The sampling method in the present research was a purposive sampling, and theoretical saturation acquired by conducting 18 interviews. Semi-structured interviews were used to collect data. The data analysis method is based on coding and categorization. Data analysis was done using MAXQDA 2020 software. The findings of the research showed that all the criteria were confirmed, and it was found that Kendall's coordination coefficient improved in each round compared to the previous round. According to the analysis of the findings, all the identified variables are of appropriate importance and therefore the phenomenological model was presented. In the final results of the research, the main themes with the titles, human resource management, process system, knowledge concealment, and consequences were identified, and each main theme consists of several sub-themes as described in the text of the article.
Extended Abstract
Introduction
Knowledge sharing is a voluntary activity, and organizations are trying to find ways to encourage people to share their knowledge with other members. Due to the strategic importance of knowledge sharing within organizations, several studies have been conducted to investigate the behavioral records related to knowledge sharing by individuals in the workplace. The fact that knowledge hiding is a common phenomenon in organizations was highlighted in a research conducted by Mil & Mil (2006). This study showed that 20% of employees hide their knowledge from their colleagues because they believe that knowledge belongs to privacy and should not be shared (Peng, 2015).
Van & Hoff (2017) argued that knowledge hiding occurs when an individual does not intentionally disseminate his knowledge to other members of the organization (Kang et al, 2017; Hernaus et al, 2016). In their research model, they showed that knowledge concealment, like knowledge sharing, can have two dimensions: explicit knowledge concealment and implicit knowledge concealment. On one hand, the concealment of explicit knowledge can be easily found in non-recording, non-classification, and non-storage; and the concealment of implicit knowledge can be found hidden in people's daily actions and mental models (Hernaus et al., 2018). Aother reasons for hiding knowledge by employees is that people consider their knowledge as an important tool that helps them to continue being a valuable person in the organization (Hosseinpour et al, 2016).
According to the explanation and explanation of the problem, the main question has been raised as follows: What are the effective factors in hiding knowledge in the country's water and sewage engineering company?
Theoretical Framework
According to Martin (2005); diverse cultures, lack of trust, lack of enough time, inefficient and fruitless communication and poor knowledge can cause knowledge to be hidden (Anand & Hassan, 2019). In most situations, organizational factors such as job participation and satisfaction, performance evaluation and performance recognition are also considered as motivators to increase and promote knowledge disclosure behavior among users. In addition, organizational culture, senior management support and organizational communication also affect knowledge disclosure behavior. Revealing knowledge is shared indirectly through learning activities existing among users (Ibrahim & Hock Heng, 2015). Weakness in the organization's reward and encouragement system is one of the factors that encourage knowledge concealment among employees. Since knowledge sharing is essentially a behavioral issue, using a reward system is one of the ways to increase the probability of this behavior from employees. If the organization does not provide material and spiritual support and appreciation to the employees who have a high motivation to share their knowledge with others, the motivation of other employees to follow this behavior will decrease and the organization's employees will manifest behaviors related to knowledge concealment.  However, when employees do not believe in the value and importance of sharing their knowledge with colleagues, even the existence of a strong motivational system cannot be effective, and the behavior of hiding knowledge always becomes one of the favorite behaviors of employees.
Haghsetan & Jantifar (2021) investigated the moderating role of professional commitment in studying the impact of perceived organizational policies on knowledge concealment (case study: Tehran's Hemian Fan Sanat Berq Company). The results show that professional commitment moderates the effect of perceived organizational policies on knowledge concealment.
Chen et al, (2020) investigated the integration of light and dark aspects of communication transparency for knowledge management and creativity: the moderating role of regulatory focus. Their findings advance the understanding of communication visibility theory and regulatory focus theory in corporate social media contexts. For employees, the findings suggest that they need to share their knowledge with other colleagues to improve their creativity. For organizations, the findings recommend that they should implement various policies that highlight the organizational focus of employees to facilitate knowledge sharing and prevent knowledge hiding.
Research methodology
This research is in the category of basic research. This research was conducted using a qualitative method and a phenomenological approach for analysis. The statistical population of the research included 18 managers, senior experts and experts of the water and sewage department who have more than 20 years of experience in the company environment and at different levels. The sampling method in this research is stratified sampling. In order to collect data, semi-structured, in-depth, collaborative and long-term interviews were used.
Research findings
The method of analyzing the collected data was based on coding and categorization and using MAXQDA 2020 software. The findings of the research showed that all the criteria were confirmed, and it was found that Kendall's coordination coefficient improved in each round compared to the previous round. According to the analysis of the findings, all the identified variables are of appropriate importance and therefore the phenomenological model was presented. In the final results of the research, the main themes with the titles of human resource management, process system, knowledge concealment, and consequences were identified, and each main theme consists of several sub-themes as described in the text of the article.
Conclusion
This research was conducted with the aim of investigating the effective factors in hiding knowledge in the country's water and sewage engineering company. The results of this research are consistent with the researches of Hoseinpour (2020), Jiang & Xu (2020), Chen et al, (2020), harma & Toshinwal (2020), and Singh (2019). The biggest reason for concealment of knowledge in the country's water and sewage company can be attributed to deliberate concealment and retaliatory concealment, which the vast majority of the interviewees mentioned directly or indirectly. Every research has its own limitations. The duty of the researcher is to express the limitations of his research and try to bring his scientific work to criticism deliberately and bravely. This part of the thesis is dedicated to this part, which states the limitations of the upcoming research from the perspective of the researcher and criticizes its shortcomings, so that the statement of the limitations determines a way to improve and advance the future research. In this regard, the limitations of the research and suggestions for future research were presented, which are:

In this research based on the phenomenological method, the modeling of knowledge concealment was discussed and finally the research model was tested in the relevant statistical population. Therefore, for a more accurate and consistent review, it is suggested that the model presented in this research be tested in other similar organizations and the results obtained be compared with the results of this research.
Another limitation of this research is giving priority to conducting interviews and benefiting from the opinions of experts and professors rather than reviewing documents. Therefore, it is suggested that in the future research, the documents and records of the organization in the field of knowledge management should be studied for a more detailed examination, and appropriate categories and concepts should be extracted from them.