Evidence Summary

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Computer delivered interventions have a small effect on knowledge and some health behaviors

Portnoy DB, Scott-Sheldon LA, Johnson BT, et al. Computer-delivered interventions for health promotion and behavioral risk reduction: A meta-analysis of 75 randomized controlled trials, 1988-2007 Prev Med. 2008; 47:3-16.

Review question

What is the effect of computer-delivered intervention on individual health and health behaviors?


In 2012, 83% of Canadian households had access to the Internet, making computer delivered interventions a practical tool for promoting healthy behaviors.

Computer-delivered Interventions are interactive and can be customized to an individual’s circumstances. Interactivity and customization have been shown to be beneficial in helping people change their behavior.

How the review was done

This summary is based on a well-done meta-analysis of 75 randomized controlled trials published between 1988 and 2007. There were 35,685 participants, most of whom were adult women.

Interventions included: individual computer sessions alone or combined with electronic peer support or electronic chat rooms. Most were customized for the individual or group. There was a large range in the frequency and duration of sessions.

Computer-delivered interventions were compared with no intervention, standard education only, other brief interventions, or time-matched irrelevant content.

Outcomes considered were: overweight/obesity concerns, substance use, tobacco use, sexual behavior, physical activity, eating disorders, and other health concerns.

What the researchers found

Precursors of behavior change

  • Computer-delivered interventions led to small effects in knowledge, attitude, and intention.

Specific health behaviours

  • Computer-delivered interventions led to small effects in:  nutrition, tobacco use, substance use, binging/ purging, and sexual behavior.

General health behaviours

  • Computer-delivered interventions led to small effects in general health maintenance.

Subgroup analysis

  • Computer-delivered interventions were more effective with females, younger people, and people with prior computer experience.


Computer delivered interventions have a small impact on health knowledge, attitude, and intention as well as select health behaviors but not others.


Advanced statistical methods contrasting and combining results from different studies.
Randomized controlled trials
Studies where people are assigned to one of the treatments purely by chance.

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DISCLAIMER These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (

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