This review is an update to previous reviews. It found evidence that, compared to usual care,use of decision aids improves people’s knowledge regarding options; stimulates people to take a more active role in decision making; improves accurate risk perceptions when probabilities are included; and improves congruence between the chosen option and the patient’s values.

New for this updated review is further evidence indicating more informed, values-based choices, and improved patient-practitioner communication.

Findings show that when patients use decision aids they:

• Improve their knowledge of the options (high-quality evidence);
• Feel more informed and more clear about what matters most to them (high-quality evidence);
• Have more accurate expectations of possible benefits and harms of their options (moderate-quality evidence); and
• Participate more in decision making (moderate-quality evidence).

Patients who used decision aids that included an exercise to help them clarify what matters most to them, were more likely to reach decisions that were consistent with their values. However, the quality of the evidence was moderate for this outcome, meaning that further research may change these findings.

There is a variable effect of decision aids on length of consultation.

Consistent with findings from the previous review, decision aids have a variable effect on choices. They reduce the number of people choosing discretionary surgery and have no apparent adverse effects on health outcomes or satisfaction.

Decision aids improve communication between patients and their health practitioner.

More detailed decision aids are better than simple decision aids for improving people’s knowledge and lowering decisional conflict related to feeling uninformed and unclear about their personal values.

More research is needed to evaluate adherence with the chosen option, the associated costs, use with patients who have more limited reading skills, and the level of detail needed in a decision aid.