We show how to estimate a Cronbach's alpha reliability coefficient in Stata after running a principal component or factor analysis. Alpha evaluates to what extent items measure the same underlying content when the items are combined into a scale or used for latent variable. Stata allows for testing the reliability coefficient (alpha) of a scale only when all items receive homogenous weights. We present a user-written program that computes reliability coefficients when implementation of principal component or factor analysis shows heterogeneous item loadings. We use data on management practices from Bloom and Van Reenen (2010) to explain how to implement and interpret the adjusted internal consistency measure using afa.
Rubriek waarin 4 auteurs een aantal wetenschappelijke artikelen bespreken, van marketingprofessoren over publicaties die elke marketeer moet kennen. Karel Jan Alsem is een van de 4 auteurs. Hij bespreekt 3 artikelen over marketing en merken:1. Back to the future: integrating marketing as tactics, strategy, and organizational culture / door Fred Webster.2. The multidimensionality of brand knowlegde / door Kevin Lane Keller.3. The one thing you must get right when building a brand / door Patrick Barwise and Seán Meehan.
Background: Dependency in activities of daily living (ADL) might be caused by multidimensional frailty. Prevention is important as ADL dependency might threaten the ability to age in place. Therefore, this study aimed to assess whether protective factors, derived from a systematic literature review, moderate the relationship between multidimensional frailty and ADL dependency, and whether this differs across age groups. Methods: A longitudinal study with a follow–up after 24 months was conducted among 1027 communitydwelling people aged ≥65 years. Multidimensional frailty was measured with the Tilburg Frailty Indicator, and ADL dependency with the ADL subscale from the Groningen Activity Restriction Scale. Other measures included socio-demographic characteristics and seven protective factors against ADL dependency, such as physical activity and non-smoking. Logistic regression analyses with interaction terms were conducted. Results: Frail older people had a twofold risk of developing ADL dependency after 24 months in comparison to non-frail older people (OR=2.12, 95% CI=1.45–3.00). The selected protective factors against ADL dependency did not significantly moderate this relationship. Nonetheless, higher levels of physical activity decreased the risk of becoming ADL dependent (OR=0.67, 95% CI=0.46–0.98), as well as having sufficient financial resources (OR=0.49, 95% CI=0.35–0.71). Conclusion: Multidimensional frail older people have a higher risk of developing ADL dependency. The studied protective factors against ADL dependency did not significantly moderate this relationship.
