Open-ended interview questions and saturation.

Area of Science:

• Qualitative Research Methods
• Social Sciences
• Psychology

Background:

• Traditional qualitative research often relies on thematic saturation, a point where new information diminishes.
• Determining adequate sample size in qualitative studies remains a challenge, often based on custom or saturation.
• Existing methods may not efficiently capture the most critical information within a study domain.

Purpose of the Study:

• To propose and test a refined definition of saturation based on identifying salient items.
• To explore the relationship between saturation, salience, sample size, and domain size in qualitative interviews.
• To advance the concept of 'saturation in salience' for more efficient sample size determination.

Main Methods:

• Analysis of 28 interview datasets (1,147 total interviews) across 18 topical domains.
• Exploration of saturation, salience, sample size, and domain size.
• Comparison of sample sizes required for thematic saturation versus capturing salient items.

Main Results:

• The median sample size to reach thematic saturation (less than one new item per person) was 75 (range: 15-194).
• Salience, defined by prevalence and cultural importance, proved a more useful concept for sample size adequacy than thematic saturation.
• Small samples (n=10) captured 95% of salient ideas with exhaustive listing, while limited responses captured only 53%.

Conclusions:

• Saturation in salience offers a more practical approach to determining adequate sample sizes in qualitative research.
• Probing to increase information per respondent enhances sample efficiency and the retrieval of salient items.
• Focusing on salient items, rather than exhaustive thematic saturation, improves the utility of qualitative data collection.