Students in both experimental groups were applied the student information form and the pretest of the CRCF between May 18 and 20, 2021 before the education. The schedule of the education intervention was determined according to the convenience of the students in the experimental group. Accordingly, the experimental group was given education between June 8 and 11, 2021. After the education sessions were completed, experimental groups were applied the CRCF as a posttest on June 28, 2021. The students in the experimental group were asked to fill out the "Student Satisfaction with Education Questionnaire" and the "Form for Views on the Education" online.

Students in control groups were applied the student information form and the pretest of the CRCF between May 18 and 20, 2021 before the education. The students in the control group continued their current standard education process. After the education sessions were completed, control groups were applied the CRCF as a posttest on June 28, 2021.

The education phase This stage included the explanation of the CR process, the analysis of CR cases, the drafting of new cases suitable for the CR process by students, and the analysis process.

The education program was carried out on a web platform (Zoom) consistent with the changes in the COVID-19 pandemic process. The CR cases to be used in case-based education were sent to the students via e-mail before the group interview to make sure students came prepared for the group discussion. In case-based education, after the students read the case, they were asked some questions to determine their decisions and reasoning.

This form consists of 9 questions, including students' nicknames, age, gender, duration of clinical experience, level of school success, and views on the nursing process

There were 10 clinical cases on the CRCF prepared for the objectives of these three steps in students' clinical reasoning process. The cases involved critical illness, and early warning findings that show worsening in critical illness and are used to determine priority nursing diagnosis.

Five people, who were experts in the field of medical nursing and had clinical experience, were consulted between February 15 and 28, 2021 to confirm the clinical accuracy and reality of CR cases and their content and comprehensibility. The content validity index of expert opinions evaluated with the Davis technique was determined as 1.

A questionnaire adapted from the study of Lee et al. (2010) was used to evaluate students' satisfaction with the education given. A 6-point Likert-type scale (1= strongly disagree, 6= strongly agree) was used to evaluate the ten items of the questionnaire. The 10th item on the questionnaire is reverse coded. High scores on the questionnaire indicate a high level of satisfaction.