Public policies are considered solutions to solve the country's public problems; these issues have multiple dimensions, but often many of their dimensions, including cultural and religious ones are mostly neglected .The aim of this research is to determine that to obtain a holistic and inner harmony between the different aspects of the knowledge of a problem, is there any need for identifying and designating a common ground for their integration. This common ground could be thematic, operational, procedural, etc. This is an applied research which has been conducted as a survey by using a quantitative method to collect and analyze data. The statistical population consists of PhD candidates in public policy or other disciplines as well as PhD graduates who have cooperated with the country's policy-making institutions. The authors used purposive sampling method. Their sample size consisted of 30 persons and to measure respondents' opinion, the Likert scale questionnaire was used. The obtained data were tested by single-sample tests, and then they were ranked by Friedman test. Test results indicate a serious need to understand the common ground between knowledge for use in public policy- making, and finally, the authors propose several strategies for policy-makers and scholars.