title: Assessment of Statistical Methodologies and Pitfalls of Dissertations Carried Out at National Cancer Institute, Cairo University
abstract: Purpose: To identify statistical errors and pitfalls in dissertations performed as part of the requirements for the Medical
  Doctorate (MD) degree at the National Cancer Institute (NCI), Cairo University (CU) to improve the quality of medical
  research. Methods: A critical assessment of 62 MD dissertations conducted in 3 departments at NCI, CU, between
  2009 and 2013 was carried out regarding statistical methodology and presentation of the results. To detect differences in
  study characteristics over time, grouping was into two periods; 2009-2010 and 2011-2013. Results: Statistical methods
  were appropriate in only 13 studies (24.5%). The most common statistical tests applied were chi-square, log-rank, and
  Mann-Whitney tests. Four studies estimated sample size and/or power. Only 37.1% and 38.7% of dissertation results
  supported aims and answered the research questions, respectively. Most of results were misinterpreted (82.3%) with
  misuse of statistical terminology (77.4%). Tabular and graphical data display was independently informative in only 36
  dissertations (58.1%) with accurate titles and labels in only 17 (27.4%). Statistical tests fulfilled the assumptions only
  in 29 studies; with evident misuse in 33. Ten dissertations reported non-significance regarding their primary outcome
  measure; the median power of the test was 35.5% (range: 6-60%). There was no significant change in the characteristics
  between the time periods. Conclusion: MD dissertations at NCI have many epidemiological and statistical defects that
  may compromise the external validity of the results. It is recommended to involve a biostatistician from the very start
  to improve study design, sample size calculation, end points estimation and measures.
authors.affiliation: Department of Biostatistics and Cancer Epidemiology, National Cancer Institute, Cairo University, Egypt. Email: mailbox_mcs@yahoo.com
authors.forename: Rasha M
authors.initials: RM
authors.lastname: Allam
authors.forename: Maissa K
authors.initials: MK
authors.lastname: Noaman
authors.forename: Manar M
authors.initials: MM
authors.lastname: Moneer
authors.forename: Inas A
authors.initials: IA
authors.lastname: Elattar
keywords: MD theses; National Cancer Institute; study design; statistical methodology