Measuring Constructs

About the study: This was a cross-sectional study of N=1961 older Americans, ages 50-75 years, representing 5 ethnic groups. A telephone survey was administered to assess barriers to flu vaccinations using the HBM constructs below.

Constructs measured: Perceived Severity, Perceived Susceptibility, Perceived Barriers

Construct Survey Item Number of Items in the Scale Response Categories
Perceived Severity How would getting the flu affect your life? 1 3 point scale ranging from "make you very sick" to "is no big deal."
Perceived Susceptibility How concerned are you about getting the flu? 1 3 point scale ranging from "very concerned" to "not at all concerned"
Perceived Barriers What is the main reason you did not get a flu shot in the past year? 1 (open-ended question) Coded as 12 response categories

  • Strengths:
    • Three different constructs were measured using an ethnically diverse sample population.
  • Limitations:
    • Only one item was used to measure each of the 3 respective HBM constructs.
    • Study participants were recruited from faith-based congregations in two cities, which limited generalizability.
    • Constructs were not tested for reliability nor was the validity (i.e. content, criterion and/or construct) examined before use.

Source: Chen J.Y., Fox S.A., Cantrell C.H., Stockdale S.E., Kagawa-Singer M. (2007). Health Disparities and Prevention: Racial/Ethnic Barriers to Flu Vaccination. Journal of Community Health, 32(1), 5-20.

About the study: This was a mixed-methods study which surveyed N= 500 pregnant women in Tanzania about their willingness to accept voluntary HIV counseling and testing. HBM constructs were applied to assess individuals' perceptions about counseling and testing and its influence on health behavior. Six focus groups totaling N= 46 pregnant women was also conducted assessing the same HBM constructs used in the survey.

Constructs Measured: Perceived Susceptibility, Perceived Severity, Perceived Barriers, Cues to Action, Self-Efficacy

Construct Survey Item/Content Area Number of Items in the Scale Response Categories
Perceived Severity To what extent one thought HIV/AIDS threatened the health of the local community? 1 4 point scale ranging from "no threat at all" to "serious threat"
Perceived Susceptibility Perceived chances of contracting HIV?

Possibility of protecting themselves?
2 5 point scale ranging from "low" to "high"
Perceived Barriers Had ever heard anyone talking in a derogatory way abut people with AIDS?

Had ever seen or heard of people with AIDS being avoided, rejected, sent away or treated badly in any way?

Disclosure, partner involvement, and confidentiality were also assessed (3 items)
5 First two items based on a 5 point scale, ranging from "never" to "frequently"

Last three items were based on a 3 point scale (see De Paoli et al, 2004)
Cues to Action Assessed readiness to accept voluntary counseling and testing

Asked if knew an adult or child who had HIV/AIDS
2 3 point scale
Self-Efficacy Based on the assumption that breastfeeding would not be advised to feed a newborn, how sure can one follow the advice

How sure can one find an alternate feeding strategy
2 Each item based on 5 point scale ranging from "definitely not confident" to "very confident"

  • Strengths:
    • Survey items had good internal consistency reliability. The scales yielded a high Cronbach's alpha for perceived susceptibility (>.7) and good Cronbach's alphas for barriers (.64), cues to action (.61), and self-efficacy (.67).
    • The study measured all HBM constructs except for "perceived benefits."
    • The study included both quantitative and qualitative methods, which assessed the same HBM constructs.
    • The study included a pre-tested questionnaire which was administered in the appropriate language (Swahili).
  • Limitations:
    • The researchers used a cross-sectional design, so they could not establish a casual relationship between independent variables (measured by the HBM constructs) and the dependent variable, "willingness to accept VCT."

Source: De Paoli M.M., Manongi R., Klepp K.I. (2004). Factors influencing acceptability of voluntary counseling and HIV-testing among pregnant women in Northern Tanzania. AIDS Care,16(4),411-2