Purpose. The effectiveness of problem-based learning (PBL) was investigated in nurse practitioner (NP) education and contrasted with the traditional lecture method of instruction.

Procedures. Fifteen NP students participated in four PBL sessions; 13 NP students served as a control group and participated in the lecture method. Both qualitative and quantitative methods of investigation were used. Qualitative inquiry included: participant-observation, group interview, open-ended questionnaire, content analysis of documents. Qualitative data were analyzed using open, axial, and selective coding. Quantitative inquiry included: problem-solving skills, attitude questionnaire, Kolb's Learning Style Inventory. Data were analyzed using analysis of variance, covariance, and a two-way analysis of variance. Content of study was the same for both groups.

Findings. Qualitative data revealed that interactions were of central importance in the development of critical thinking. Triangulation of data showed an increase in critical thinking and problem-solving skills of NP students in the PBL group. Age and current jobs revealed significant differences between the two groups $(p=.01).$ PBL group had significantly higher scores than the lecture group $(p=.01).$ Students demonstrated a highly favorable attitude toward PBL, but no significant relationship was found between students; learning characteristics and their attitudes.

Conclusion. PBL promotes NP students; critical thinking and problem-solving skills.

Recommendations. Further studies should investigate effectiveness of a combination of PBL and lecture methods of instruction. Additional studies are needed to relate students' ethnicity, clinical experience, age, and sex with PBL method of instruction. PBL should be used in several subject fields and over a longer period of time. Further study should include staff development for the facilitator role of nurse educators.