The decision between data collection using paper forms and data collection using electronic forms is largely down to review authors’ preferences. Potential advantages of paper forms include:
convenience or preference;
data extraction can be undertaken almost anywhere;
easier to create and implement (no need for computer programming or specialist software);
provides a permanent record of all manipulations and modifications (providing these manipulations and modifications are not erased); and
simple comparison of forms completed by different review authors.
Potential advantages of electronic forms include:
convenience or preference;
combines data extraction and data entry into one step;
forms may be programmed (e.g. using Microsoft Access) to ‘lead’ the author through the data collection process, for example, by posing questions that depend on answers to previous questions;
data from reviews involving large numbers of studies are more easily stored, sorted and retrieved;
allows simple conversions at the time of data extraction (e.g. standard deviations from standard errors; pounds to kilograms);
rapid comparison of forms completed by different review authors; and
environmental considerations.
Electronic systems have been developed that offer most of the advantages of both approaches (including the commercial SRS software: see www.trialstat.com). If review authors plan to develop their own electronic forms using spreadsheet or database programs, we recommend that (i) a paper form is designed first, and piloted using more than one author and several study reports; (ii) the data entry is structured in a logical manner with coding of responses as consistent and straightforward as possible; (iii) compatibility of output with RevMan is checked; and (iv) mechanisms are considered for recording, assessing and correcting data entry errors.