Optimizing presentation formats for SF-6Dv2 health status valuation: a qualitative study using cognitive interviews

The SF-6Dv2 health status valuation using the discrete choice experiment (DCE) method requires effective presentation strategies to improve respondents' overall understanding and reduce bias, particularly in online surveys. This study aimed to determine the optimal presentation formats for DCE choice tasks through qualitative interviews.

We conducted cognitive interviews with 40 South Korean adults using the think-aloud and retrospective probing methods. Participants evaluated five presentation formats (non-emphasized, bold-underlined, yellow-highlighted, graphic circle, and color-shaded) and two duration attribute placement options (upfront vs. end).

Findings revealed that the presentation format influenced three key areas: readability, comprehension, and comparative judgment. The yellow-highlighted format was the most preferred (50%), followed by the bold-underlined (37.5%) and graphic circle formats (25%), with multiple responses allowed. However, the yellow-highlighted format was criticized for being a visual burden and overlooking non-highlighted information, while the graphic format had issues such as scale direction confusion and inappropriate level summation across attributes. Meanwhile, the bold-underlined format was described easy to read, helpful in grasping the meaning quickly, and visually balanced, thereby reducing visual overload. Moreover, it supported comparative judgment by allowing users to clearly distinguish and compare domains without cognitive fatigue. Regarding duration placement, 26 participants preferred upfront placement, stating that it provided essential context for evaluation. Interestingly, the participants preferring upfront placement prioritized survival duration, while those preferring end placement emphasized the quality of life.

While the yellow-highlighted, bold-underlined, and graphic formats improved comprehension, we recommend the bold-underlined format for future SF-6Dv2 valuation studies as it balances comprehension enhancement with greater stability in choice contexts. The findings also suggest that the presentation format has the potential to influence DCE response patterns, warranting further consideration in survey design.