Background and aims: one of the main factors determining the competency of an individual in clinical judgment and decision making is the way which he/she use available evidences. The present study was set aiming at investigating the use of various evidences for clinical judgment and decision making in nursing career and assessing its relationship with various factors.

Methods: The present cross-sectional study, which was a research project approved by The National Institute for Health Research at the University of Kurdistan, Iran, was conducted during 2015. A total number of 360 nurses were selected using the multistage cluster sampling method. The tool used for collecting data was composed of three main parts; (1) demographic information and clinical condition, (2) underlying factors (seven items), and (3) the use of various evidences (11 items). A content validity ratio higher than 0.49 and content validity index higher than 0.79 confirmed that the questionnaire was validated. The reliability of the questionnaire was evaluated using the Pearson's correlation coefficient (r=0.92). Finally, the data were analyzed using SPSS software package and various statistical tests, such as Pearson's correlation coefficient and multiple regressions.

Results: there was observed a negative significant correlation between the level and type of evidence used by individuals with the urgency of the clinical condition (r=–0.58). Further, there was a positive significant correlation between the level and type of evidence used by individuals and their education level (P-value<0.05). However, no significant correlation was found between the use of evidence with age, experience, and gender. Regarding the underlying factors in using evidence, there was a positive significant correlation between the use of evidence with the availability of resources and clinical equipment (r=0.92), educational facilities (r=0.64), management support (r=0.76), organization (r=0.58), and physicians (r=0.84) (P-value<0.05).

Conclusion: it can be concluded from the present study that the improvement of clinical condition and skills in emergencies and enhancing the availability of required resources and facilities would facilitate the use of evidences. Moreover, it was observed that nurses were less desired to use clinical guidelines and scientific documents, and they preferred to use other tools such as experience, regulations standards, clinical and Para-clinical documents. Hence, it is recommended that the availability of these resources should be promoted.