title: The effectiveness of problem-based learning on development of nursing students' critical thinking: a systematic review and meta-analysis.
abstract: OBJECTIVE
  The objective of this systematic review and meta-analysis was to estimate the effectiveness of problem-based learning in developing nursing students' critical thinking.
  
  
  METHODS
  Searches of PubMed, EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Proquest, Cochrane Central Register of Controlled Trials (CENTRAL) and China National Knowledge Infrastructure (CNKI) were undertaken to identify randomized controlled trails from 1965 to December 2012, comparing problem-based learning with traditional lectures on the effectiveness of development of nursing students' critical thinking, with no language limitation. The mesh-terms or key words used in the search were problem-based learning, thinking, critical thinking, nursing, nursing education, nurse education, nurse students, nursing students and pupil nurse.
  
  
  METHODS
  Two reviewers independently assessed eligibility and extracted data. Quality assessment was conducted independently by two reviewers using the Cochrane Collaboration's Risk of Bias Tool. We analyzed critical thinking scores (continuous outcomes) using a standardized mean difference (SMD) or weighted mean difference (WMD) with a 95% confidence intervals (CIs). Heterogeneity was assessed using the Cochran's Q statistic and I(2) statistic. Publication bias was assessed by means of funnel plot and Egger's test of asymmetry.
  
  
  RESULTS
  Nine articles representing eight randomized controlled trials were included in the meta-analysis. Most studies were of low risk of bias. The pooled effect size showed problem-based learning was able to improve nursing students' critical thinking (overall critical thinking scores SMD=0.33, 95%CI=0.13-0.52, P=0.0009), compared with traditional lectures. There was low heterogeneity (overall critical thinking scores I(2)=45%, P=0.07) in the meta-analysis. No significant publication bias was observed regarding overall critical thinking scores (P=0.536). Sensitivity analysis showed that the result of our meta-analysis was reliable. Most effect sizes for subscales of the California Critical Thinking Dispositions Inventory (CCTDI) and Bloom's Taxonomy favored problem-based learning, while effect sizes for all subscales of the California Critical Thinking Skills Test (CCTST) and most subscales of the Watson-Glaser Critical Thinking Appraisal (WCGTA) were inconclusive.
  
  
  CONCLUSIONS
  The results of the current meta-analysis indicate that problem-based learning might help nursing students to improve their critical thinking. More research with larger sample size and high quality in different nursing educational contexts are required.
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China; Nursing College of Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Ling-Na
authors.initials: LN
authors.lastname: Kong
authors.affiliation: Department of Infectious Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, PR China. Electronic address: cqqinbo@126.com.
authors.forename: Bo
authors.initials: B
authors.lastname: Qin
authors.affiliation: Nursing College of Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Ying-qing
authors.initials: YQ
authors.lastname: Zhou
authors.affiliation: Nursing College of Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Shao-yu
authors.initials: SY
authors.lastname: Mou
authors.affiliation: Nursing College of Chongqing Medical University, Chongqing 400016, PR China.
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Gao
mesh_terms: D006801:Humans; D018794:Problem-Based Learning; D013338:Students, Nursing / Q000523:psychology*; D013850:Thinking
keywords: Critical thinking; Meta-analysis; Nursing education; Problem-based learning (PBL); Systematic review