Study designs of evaluations included in the review
Only randomised controlled trials (RCTs) were eligible for inclusion.
Specific interventions included in the review
Studies that assessed computer-tailored interventions, aimed at changing physical activity or nutrition behaviours, were eligible for inclusion. Tailored interventions were defined as those intended for individuals, based on their unique characteristics and derived from an assessment. The information had to be delivered in a non-personal way (such as printed format, interaction with computer or other media device). Studies assessing generic materials (aimed at a particular population), or those that used computer-tailored interventions as part of a wider package, were excluded.
In the included studies most interventions were informed by explicit theoretical behavioural models. They included feedback on current behaviour, awareness of performance or intentions/self efficacy, as well as information on knowledge, benefits, barriers to change, etc. Most computer-tailored interventions were delivered via letters, pamphlets, or brochures or computer; others were delivered using text and video. None used the Internet. Most of the comparator groups received no information or generic information, but some received self-help workbooks, video modelling/lecture or intake feedback. Most interventions involved a single contact.
Participants included in the review
Studies on apparently healthy adults were eligible for inclusion (i.e. those aimed at primary prevention of disease). In the included studies some people were recruited through work sites, colleges, medical practices, supermarkets and churches; others included recipients of welfare benefits or the general population. Some included studies recruited only sedentary people, while in others people were overweight or had risk factors for cardiovascular diseases.
Outcomes assessed in the review
Studies that assessed changes in physical activity or nutrition behaviours were eligible for inclusion. The included studies assessed physical activity, effects on fat intake and fruit and vegetable consumption, and other dietary behaviours (fibre and calcium intake or weight loss). Changes were assessed using questionnaires, food frequency questionnaires, food diaries, or shopping receipts. Most studies use validated questionnaires.
How were decisions on the relevance of primary studies made?
Two reviewers independently assessed papers for inclusion in the review. Any disagreements were resolved by consensus, with the help of a third reviewer.