Table 2. Purpose, illustrative measures and limitations of each approach.

Purpose	Illustrative measures	Limitations
Perspectives on contraceptive method characteristics
•   Prioritize method characteristics to target in product development	•   Frequency distribution of preferred method characteristics	•   Bound by list of characteristics anticipated by the researcher •   No information on how to combine characteristics
Reactions to product in development
•   Prioritize methods for continued development efforts	•   Overall interest in using the method •   Perceived advantages and disadvantages of the method	•   Complexity of concisely describing methods •   Bound by method characteristics included in the description of the method •   Social desirability bias
Trade-offs between contraceptive method characteristics
•   Inform potential adjustments to product design in terms of trade-offs between method characteristics	•   Importance ranking of method characteristics	•   Complexity of design balancing statistical considerations, cognitive burden on respondent, and technically feasible product designs •   Bound by method characteristics included in the description of the method Unknown predictive validity
Blue-sky ideas on novel contraceptive technologies
•   Generate innovative ideas for new product designs	•   List of user-generated ideas for potential novel product designs	•   Difficulty abstracting from existing product designs among participants •   Unknown external validity