Assessing comparability of dressing disability in different countries by response conversion.

BACKGROUND Comparability of health data is a major challenge within the context of the Health Monitoring Programme of the European Commission. A common problem in surveys is that many variations of essentially the same question exist. METHODS Response conversion is a new method for improving comparability by scaling the data onto a common scale. Comparisons between member states can then be made in terms of the common scale. A first step is the construction of a conversion key. This is a relatively complex activity, but needs to be done only once. The second step is the actual data transformation. This is simple, and can be repeatedly done on a routine basis as new information arrives. Construction of the key is only possible if enough overlapping information can be found. RESULTS The method is illustrated for dressing disability from five European countries. Differences occur between countries, between sexes and between age groups. These were similar in magnitude. CONCLUSION Response conversion is a new method for enhancing comparability among existing data. Conversion can only be done if a key is available. More work is needed to establish the technique. Future implications within the Health Monitoring Programme are discussed.