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Open-ended interview questions and saturation

Sample size determination for open-ended questions or qualitative interviews relies primarily on custom and finding the point where little new information is obtained (thematic saturation). Here, we propose and test a refined definition of saturation as obtaining the most salient items in a set of q...

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Autores principales: Weller, Susan C., Vickers, Ben, Bernard, H. Russell, Blackburn, Alyssa M., Borgatti, Stephen, Gravlee, Clarence C., Johnson, Jeffrey C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6010234/
https://www.ncbi.nlm.nih.gov/pubmed/29924873
http://dx.doi.org/10.1371/journal.pone.0198606
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author Weller, Susan C.
Vickers, Ben
Bernard, H. Russell
Blackburn, Alyssa M.
Borgatti, Stephen
Gravlee, Clarence C.
Johnson, Jeffrey C.
author_facet Weller, Susan C.
Vickers, Ben
Bernard, H. Russell
Blackburn, Alyssa M.
Borgatti, Stephen
Gravlee, Clarence C.
Johnson, Jeffrey C.
author_sort Weller, Susan C.
collection PubMed
description Sample size determination for open-ended questions or qualitative interviews relies primarily on custom and finding the point where little new information is obtained (thematic saturation). Here, we propose and test a refined definition of saturation as obtaining the most salient items in a set of qualitative interviews (where items can be material things or concepts, depending on the topic of study) rather than attempting to obtain all the items. Salient items have higher prevalence and are more culturally important. To do this, we explore saturation, salience, sample size, and domain size in 28 sets of interviews in which respondents were asked to list all the things they could think of in one of 18 topical domains. The domains—like kinds of fruits (highly bounded) and things that mothers do (unbounded)—varied greatly in size. The datasets comprise 20–99 interviews each (1,147 total interviews). When saturation was defined as the point where less than one new item per person would be expected, the median sample size for reaching saturation was 75 (range = 15–194). Thematic saturation was, as expected, related to domain size. It was also related to the amount of information contributed by each respondent but, unexpectedly, was reached more quickly when respondents contributed less information. In contrast, a greater amount of information per person increased the retrieval of salient items. Even small samples (n = 10) produced 95% of the most salient ideas with exhaustive listing, but only 53% of those items were captured with limited responses per person (three). For most domains, item salience appeared to be a more useful concept for thinking about sample size adequacy than finding the point of thematic saturation. Thus, we advance the concept of saturation in salience and emphasize probing to increase the amount of information collected per respondent to increase sample efficiency.
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spelling pubmed-60102342018-07-06 Open-ended interview questions and saturation Weller, Susan C. Vickers, Ben Bernard, H. Russell Blackburn, Alyssa M. Borgatti, Stephen Gravlee, Clarence C. Johnson, Jeffrey C. PLoS One Research Article Sample size determination for open-ended questions or qualitative interviews relies primarily on custom and finding the point where little new information is obtained (thematic saturation). Here, we propose and test a refined definition of saturation as obtaining the most salient items in a set of qualitative interviews (where items can be material things or concepts, depending on the topic of study) rather than attempting to obtain all the items. Salient items have higher prevalence and are more culturally important. To do this, we explore saturation, salience, sample size, and domain size in 28 sets of interviews in which respondents were asked to list all the things they could think of in one of 18 topical domains. The domains—like kinds of fruits (highly bounded) and things that mothers do (unbounded)—varied greatly in size. The datasets comprise 20–99 interviews each (1,147 total interviews). When saturation was defined as the point where less than one new item per person would be expected, the median sample size for reaching saturation was 75 (range = 15–194). Thematic saturation was, as expected, related to domain size. It was also related to the amount of information contributed by each respondent but, unexpectedly, was reached more quickly when respondents contributed less information. In contrast, a greater amount of information per person increased the retrieval of salient items. Even small samples (n = 10) produced 95% of the most salient ideas with exhaustive listing, but only 53% of those items were captured with limited responses per person (three). For most domains, item salience appeared to be a more useful concept for thinking about sample size adequacy than finding the point of thematic saturation. Thus, we advance the concept of saturation in salience and emphasize probing to increase the amount of information collected per respondent to increase sample efficiency. Public Library of Science 2018-06-20 /pmc/articles/PMC6010234/ /pubmed/29924873 http://dx.doi.org/10.1371/journal.pone.0198606 Text en © 2018 Weller et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
spellingShingle Research Article
Weller, Susan C.
Vickers, Ben
Bernard, H. Russell
Blackburn, Alyssa M.
Borgatti, Stephen
Gravlee, Clarence C.
Johnson, Jeffrey C.
Open-ended interview questions and saturation
title Open-ended interview questions and saturation
title_full Open-ended interview questions and saturation
title_fullStr Open-ended interview questions and saturation
title_full_unstemmed Open-ended interview questions and saturation
title_short Open-ended interview questions and saturation
title_sort open-ended interview questions and saturation
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6010234/
https://www.ncbi.nlm.nih.gov/pubmed/29924873
http://dx.doi.org/10.1371/journal.pone.0198606
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