Data extraction and analysis

Using a data extraction form designed by the authors, JH extracted descriptive data on study context and study objectives, study methods, sample characteristics, sample size, response rate, study period and choices available to study participants, and also wrote a text description summarising the preference-related findings in each report. These data were cross-checked by YL against the full-text articles and any queries regarding the data or interpretation were discussed and resolved. In order to facilitate the production of a narrative summary, findings relating to preferences were coded using a set of keywords e.g. continuity of care, pain relief in labour, decision making, ‘home-like’. These keywords were refined as coding progressed and papers were iteratively recoded where necessary. Eppi-Reviewer 4 software [14] was used for data extraction, coding and data management.