Utilizing content-knowledge questionnaires to assess study eligibility and detect deceptive responding

Justin C. Strickland, William W. Stoops

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Background: Deceptive responding during eligibility screening presents a significant concern for assessing inclusion/exclusion criteria. This problem is compounded in settings for which biomarkers or other objective verification (e.g., urinalysis) are not feasible.Objectives: Introduce and describe content-knowledge questionnaires as an objective method for collaterally assessing study eligibility.Methods: Participants (N = 3772; 66.1% female) recruited using the crowdsourcing resource Amazon Mechanical Turk (mTurk) completed a Cannabis Knowledge Questionnaire (CKQ). The CKQ contained four-items indexing knowledge of typical cannabis costs, weights, and terminology. Self-reported cannabis use history was collected and compared to individual item and total scale scores. A separate in-laboratory assessment evaluated participants during in-person screening for cannabis, alcohol, and cocaine research protocols (N = 43).Results: Good internal consistency (α =.74) was observed. The most common correctly answered question was about dabbing (41.4%) followed by cannabis cost (37.6%), hybrid strains (36.6%), and estimated weight (29.7%). Current cannabis use was associated with large effect size increases in the rate of correct responses (RR = 3.64) as well as odds of a correct response on individual items (OR = 5.88–21.48). In the laboratory study, participants with a positive urine drug test for cannabis or those reporting lifetime regular cannabis use scored higher than those without this history (RR = 1.89–2.61).Conclusion: These findings highlight the efficiency and efficacy of including content-knowledge questionnaires for collateral assessment of study eligibility, especially when biomarkers are not possible. Future studies will be useful for extending this initial demonstration to alternative settings and substances.

Original languageEnglish
Pages (from-to)149-157
Number of pages9
JournalAmerican Journal of Drug and Alcohol Abuse
Issue number2
StatePublished - Mar 3 2020

Bibliographical note

Publisher Copyright:
© 2019, © 2019 Taylor & Francis Group, LLC.


  • Cannabis
  • crowdsourcing
  • deception
  • enrollment
  • internet
  • mTurk
  • substance use

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Clinical Psychology
  • Psychiatry and Mental health


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