A pen sent with trial questionnaire and/or study materials, which serves as a reminder to return study items. The pen can contain the research institution details and/or the trial name and logo
Addition of a pen may increase retention slightly.
An increase of 2% (95% confidence interval = 0% to 4%).
GRADE Low certainty.
We recommend that trialists consider adding a pen to invitation packs or questionnaires.
See Resource bundle below for support materials
Imagine initial retention is 65% of those approached. You have a trial with 100 participants that needs responses from 80 to meet its statistical power calculations. Retention of 65% means that you will be 15 responses short (see chart below).
Now imagine including a pen with study materials. The chart below shows the impact of an absolute increase of 2% (95% CI = 0% to 4%). Retention is now 67%, which means our best estimate is that you would now only be 13 responses short.
Trial Forge will make trials more efficient by looking for marginal gains across all trial processes, from research question to implementation into routine care. It will encourage everyone connected with trials to be more sceptical of what we do by asking for the evidence behind all of our trial decisions.