Sample extensiveness in qualitative nutrition education research.
OBJECTIVE
Extensiveness represents the amount of information gathered in qualitative research. This study examined sample extensiveness in qualitative nutrition education research.


METHODS
Retrospective analysis was performed on articles published in the Journal of Nutrition Education (JNE) from 1969 to 1999 (Volumes 1 to 31).


METHODS
Content analysis was used to code articles and the studies they reported as units of analysis.


METHODS
Articles were coded to determine whether they included one or more studies using qualitative research and, if so, the types of qualitative studies performed, the sample extensiveness of each study, and mention of sample extensiveness limitations in the article.


METHODS
The statistics used were univariate (counts, percentages, means, medians, modes, ranges) and bivariate (chi-square, correlations).


RESULTS
Of the published JNE articles, 71 (8%) used qualitative methods, and most (85%) qualitative articles were published in the 1990s. Some (19%) of these articles reported using multiple qualitative methods. The 30 studies using individual interviews interviewed an average of 45 people (range 15-155). The 38 studies using group interviews averaged 15 groups (range 1-180) and 141 people (range 9-900). Ten studies used observation/fieldwork, and eight used other types of qualitative research, with mixed [corrected] patterns of sample extensiveness in those studies. Few articles made specific statements about limitations based on sample extensiveness.


CONCLUSIONS
Sample extensiveness in qualitative research in JNE varied considerably. Future qualitative research would benefit from more explicit attention to sample extensiveness.
Sobal
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Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA. js57@cornell.edu
D000328:Adult; D003625:Data Collection; D005069:Evaluation Studies as Topic; D006801:Humans; D007407:Interviews as Topic; D052756:Nutritional Sciences / Q000193:education*; D019370:Observation; D012107:Research Design; D012189:Retrospective Studies; D012494:Sampling Studies