Alphonsus Chong's Personal Wiki

Rasch measurement vs Item response theory

1. psychometric – originally psychology but now broadened
2. psychometric: methods for developing and evaluating rating scales, and for analyzing their data

1. for properties that we can't measure directly e.g. happiness, disability (vs weight)
2. latent traits – “inferred variabllle” = aka 'property', 'trait', 'concept', 'aspect'
3. Dichotomous (RMI) vs polytomous (3 or more)
4. Direct also opposite RMI vs MSIS-29

 " extent to which a quantitative conceptualization has been operationalized successfully "

1. Traditional 3: reliability, validity, responsiveness
2. Hobart 6:

• Data quality
• scaling (assumptions)
• targetting
• reliability
• validity
• responsiveness

1. Weak true core theory
2. 'weak assumptions leads to weak conclusions'

Limitations of traditional psychometric methods

1. ordered counts are not interval measures
2. results for scales are sample dependent (therefore unstable)
3. results for samples are scale dependent
4. missing data
5. SEM
6. scaling

Hobart, J., & Cano, S. (2009). Improving the evaluation of therapeutic interventions in multiple sclerosis: The role of new psychometric methods. Health Technology Assessment, 13(12). https://doi.org/10.3310/hta13120

1. created: 2021-03-11