STEPS conceptual framework
The STEPS approach focuses on obtaining core data, at each level, on the established risk factors that determine the major disease burden. It is sufficiently flexible to allow each country to expand on the core variables and risk factors, and to incorporate optional modules related to local or regional interests.
Step 1- Questionnaire-based assessment
The STEPS approach has three levels and within each level, risk factor assessment is divided into core, expanded, and optional modules. Step 1 contains as the core or “minimum set”, self-report measures that all countries should obtain. In addition to socio-economic data, data on tobacco and alcohol use, some measure of nutritional status and physical inactivity are included as markers of current and future health status. Standard WHO definitions for measuring the prevalence of tobacco use and alcohol consumption and internationally derived measures of physical activity are recommended. The information can be used not only for within-country trends, but also for comparisons across countries. The questionnaires used in the core data set are simple and few in number and are not intended to give a complete picture of each behaviour but rather to provide information on the population distribution of risk.
Step 2- Simple physical measurements
Step 2 adds to Step 1 by the inclusion of simple physical measurements, such as height, weight, waist circumference, and blood pressure. Step 1 and Step 2 are desirable and appropriate for most developing countries.
Step 3- Biochemical Measurements
Step 3 includes Steps 1 and 2 and adds biochemical measurements. All the core items from Steps 1 and 2 can be readily assessed and are not made more complex if the expanded items are added. However, additional information at Step 3 is of a biochemical nature and requires access to the appropriate standardized laboratories. Collecting and analysing blood samples is a relatively complex process and can be done only in the context of a comprehensive survey and in settings where appropriate resources are available. The addition of Step 3 can increase the cost and complexity of data collection.