Table 1 A guiding matrix for using the TRACT Screening Checklist

Governance

Absent or retrospective registration of RCTs. This is relevant for RCTs commencing after 2010

Prospective registration

RCTs commencing before 2010

Absent or retrospective RCTs

Discrepancy of > 15% between the intended sample size in the trial registration compared to the actual sample size achieved in the RCT

If registration is retrospective, then by definition the RCT sample size will be the same as the registered number

Discrepancy of < 15%

No trial registration to provide intended sample size

Discrepancy of > 15%

Absent or vague description of research ethics or apparent concerns regarding ethics

Thorough description of ethical concerns and research ethics obtained

Unclear ethical concerns in the setting of ethics approval

Absent description

Author Group

Consider using publisher services such as Scopus or Clarivate to identify authors and their publications

Number of authors \(\le\) 3 or low author to study size ratio

^a

Other studies of authors have been retracted not on request of the authors

Consider checking http://retractiondatabase.org/RetractionSearch.aspx

No identifiable retracted studies

Retracted studies on the request of the author with unclear explanation

Known retracted studies

Large number of RCTs published in a short time frame by one author/in one institute

This ‘number’ is subjective based on the field of study, author or author group and timeframe

^a

Identical common names of authors with multiple articles in a short time frame

^a

Plausibility of Intervention Usage

Insufficient or implausible description of allocation concealment (e.g. two interventions but only one placebo)

Consider if the interventions and control/placebo are explained sufficiently enough to be repeated in another experiment

Description of allocation concealment is detailed enough to replicate

Allocation concealment described is plausible and reasonable but requires more detail

No description of allocation concealment

Unnecessary or illogical description of methodological standards (e.g. use of sealed envelopes in a placebo-controlled trial)

Methodology ideal for study design

Methodology reasonable but not gold standard for study design

Methodology inappropriate for study design

Timeframe

Fast recruitment of participants within the study time (especially single centre studies)

^a

Short or impossible time frame between ending recruitment/follow up and submission of the paper (take into account time to outcome e.g. live birth, pregnancy outcome etc.)

The recruitment time frame is from the date of the first recruited patient to the date of the last recruited patient

^a

Drop-Out Rates

Zero participants lost to follow up or no reasons mentioned for loss of follow up

Especially in cases of long follow-up (e.g. multiple months) and/or multiple cycles of or long-lasting interventions

Rationale for patients lost to follow-up provided

Patients lost to follow-up with insufficient rationale provided

Zero patients lost to follow-up despite long follow-up period

Ideal number of losses to follow up resulting in perfectly rounded number in each group (e.g. groups of 50 or 100)

^a

Almost exact numbers lost to follow-up group

Exact and -perfectly rounded numbers lost to follow-up in each group

Baseline Characteristics

No or few baseline (< 5) characteristics presented

An adequate amount of baseline characteristics that are relevant to the study

An adequate amount of baseline characteristics provided but with unclear relevance

No baseline characteristics provided

Implausible patient characteristics judging from common sense, the literature and local data (e.g. similar standard deviations for completely different characteristics with different means and distributions)

^a

Perfect balance for multiple baseline characteristics or significant/large differences between baseline characteristics

^a

Identical numbers between groups of multiple baseline characteristics

Important prognostic factors are not reported as baseline characteristics

^a

^aOutcomes

Effect size that is much larger than in other RCTs regarding the same topic

Consider utilising meta-analyses if available

^a

Conflicting information between outcomes (e.g. more ongoing pregnancies than clinical pregnancies)

^a

Change in primary outcome from registration to publication

No change in primary outcome

Single primary outcome in registration included as part of multiple primary outcomes in publication

Primary outcome in registration no longer mentioned or analysed in publication