Education and Human Sciences, College of (CEHS)


First Advisor

Professor Wayne A. Babchuk

Date of this Version


Document Type



A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Psychological Studies in Education (Quantitative, Qualitative, and Psychometric Methods), Under the Supervision of Professor Wayne A. Babchuk. Lincoln, Nebraska: August, 2023

Copyright © 2023 Analay Perez


Sampling is integral to the research process and, if not appropriately addressed, can affect the meta-inferences of the mixed methods study. Sampling is also closely related to recruitment, retention, and additional methodological components. Sampling issues are magnified in social and health sciences intervention research due to the temporal placement of data collection and analysis. Limited research has examined sampling based on researchers’ rationales and decision-making across mixed methods psychological intervention research. This study explored this phenomenon to develop and refine a list of practical recommendations for sampling in mixed methods that were tested using content validity.

Using an exploratory sequential mixed methods case study design, the first phase consisted of a qualitative case study using two data sources, a mixed method research-systematic methodological review (MMR-SMR), and semi-structured interviews with researchers who have conducted a mixed methods psychological intervention study. Forty studies were identified through the MMR-SMR and coded using a codebook. Semi-structured interviews were conducted with researchers (N = 10), and several overarching themes were identified. Through building integration, the qualitative findings informed the development of a list of preliminary recommendations that was refined using a modified e-Delphi study for the quantitative phase. Experts (i.e., mixed methods research methodologists) were asked to rate each recommendation's relevancy. Agreement consensus was established based on median and item-content validity index (I-CVI) values to test a component of content validity across each recommendation. Participants rated recommendations across Round 1 (N = 10) and Round 2 (N = 9). Recommendations were modified based on participant ratings and open-ended responses.

The final list consisted of 20 recommendations, each demonstrating adequate evidence of content validity. These recommendations span various categories, including recruitment, retention, sampling across mixed methods research designs, data collection, integrating mixed methods samples, and temporal placement of qualitative strand. Multiple audiences, including researchers, mixed methods research methodologists, and grant and journal reviewers, can use the list of recommendations to guide sampling decisions in mixed methods psychological intervention research.

Advisor: Wayne A. Babchuk