Statisticians are in short supply, so scientific journals find it hard to get one of us to review the papers that have been submitted to them. And yet the huge majority of these papers rely heavily on stats for their conclusions. As a reviewer, I see the same problems appearing over and over, but I know how hard it is for most scientists to find a friendly statistician to help them make it better. So, I present this log of all the papers I have reviewed, anonymised, giving the month of review, study design and broad outline of what was good or bad from a stats point of view. I hope this helps some authors improve the presentation of their work and avoid the most common problems.
I started this in November 2013, and am working backwards as well as recording new reviews, although the retrospective information might be patchy.
- November 2012, randomised controlled trial, recommended rejection. Sample size was based on an unrealistic Minimum Clinically Important Difference from prior research uncharacteristic of the primary outcome, and thus the study was unable to demonstrate benefit, and unethical because the primary outcome was about efficiency of the health system while benefit to patients had already been demonstrated, yet the intervention was withheld in the control group. Power to detect adverse events was even lower as a result, yet bold statements about safety were made. A flawed piece of work that put hospital patients at risk with no chance of ever demonstrating anything, this study should never have been approved in the first place. Of interest to scholars of evidence-based medicine, this study has now been printed by Elsevier in a lesser journal, unchanged from the version I reviewed. Such is life; I only hope the authors learnt something from the review to outweigh the reward they felt at finally getting it published.
- November 2013, cross-sectional survey, recommended rejection. Estimates were adjusted for covariates (not confounders) when it was not relevant to do so, grammar was poor and confusing in places, odds ratios were used when relative risks would be clearer, t-tests and chi-squareds were carried out and reported without any hypothesis being clearly stated or justified
- November 2013, exploratory / correlation study, recommended major revision then rejection when authors declined to revise the analysis. Ordinal data analysed as nominal, causing an error crossing p=0.05.
- March 2014, randomised controlled trial, recommended rejection. Estimates were adjusted for covariates when it was not relevant to do so, bold conclusions are made without justification.
- April 2014, mixed methods systematic review, recommended minor changes around clarity of writing and details of one calculation.
- May 2014, meta-analysis, recommended acceptance – conducted to current best practice, clearly written and on a useful topic.
- July 2014, ecological analysis, recommended major revision. Pretty ropy on several fronts, but perhaps most importantly that any variables the authors could find had been thrown into an “adjusted” analysis with clearly no concept of what that meant or was supposed to do. Wildly optimistic conclusions too. Came back for re-review in September 2014 with toned-down conclusions and clarity about what had been included as covariates but the same issue of throwing the kitchen sink in. More “major revisions”; and don’t even think about sending it voetstoots to a lesser journal because I’ll be watching for it! (As of September 2015, I find no sign of it online)
- July 2014, some other study I can’t find right now…
- September 2014, cohort study. Clear, appropriate, important. Just a couple of minor additions to the discussion requested.
- February 2015, secondary analysis of routine data, no clear question, no clear methods, no justification of adjustment, doesn’t contribute anything that we haven’t already known for 20 years and more. Reject.
- February 2015, revision of some previously rejected paper where the authors try to wriggle out of any work by refuting basic statistical facts. Straight to the 5th circle of hell.
- March 2015, statistical methods paper. Helpful, practical, clearly written. Only the very merest of amendments.
- April 2015, secondary analysis of public-domain data. Inappropriate analysis, leading to meaningless conclusions. Reject.
- April 2015, retrospective cohort study, can’t find the comments any more… but I think I recommended some level of revisions
- September 2015, survey of a specific health service in a hard-to-reach population. Appropriate to the question, novel and important. Some amendments to graphics and tables were suggested. Minor revisions.
- March 2016, case series developing a prognostic score. Nice analysis, written very well, and a really important topic. My only quibbles were about assuming linear effects. Accept subject to discretionary changes.
- October 2016, cohort study. Adjusted for stuff that probably isn’t confounding, and adjusting (Cox regression) for competing risks when they should be recognised as such. Various facts about the participants that are not declared. Major revisions.
- October 2016 diagnostic study meta-analysis. Well done, clearly explained. A few things could be spelled out more. Minor revisions.
- November 2016, kind of a diagnostic study…, well-done, well-written, but very limited in scope and hard to tell what the implications for practice might be. Left in the lap of the
- December 2016, observational study of risk factors, using binary outcomes but would be more powerful with time-to-event if possible. Competing risks would have to be used in that case. Otherwise, nice.