Intervention Evaluation
There are three distinct times during an intervention when an evaluation can be conducted, before, during and after the intervention. Evaluation before the onset of your intervention is similar to a needs assessment. When conducting an evaluation at this stage, you are determining the starting point or baseline for your community. This will help you determine what has changed once the intervention is complete. During an intervention, you may consider collecting information that helps to ensure that your intervention is being carried out according to plan and identifies areas that can be improved while the intervention is going on. Evaluation at the end of the intervention will provide information about whether the intervention had a positive impact on your community of interest. Evaluation at this stage helps to assess to what degree the intervention met its goals and objectives. |
There are two types of evaluation that occur before or during an intervention formative evaluation and process evaluation. Formative evaluation is one type of evaluation used to develop and refine your intervention before beginning your intervention activities. You may consider using formative evaluation to examine intervention content and short term outcomes occurring during the intervention activities. The intervention plan can be pre-tested to determine if the intervention materials will be effective and appropriate for your community of interest.
Examples of formative evaluation activities:
- Pre-testing intervention methods and materials
- Pilot tests of the intervention protocol
- Participant feedback during intervention activities
Process evaluation is used during an intervention to measure how activities are being provided, who is providing them, who is participating in the activities and how much effort is needed to provide the activities. Process evaluation measures to what degree the intervention was implemented according to the original intervention model and measures how the intervention components were received by the participant (i.e., frequency, amount, and duration of activities). You may consider using the following to capture process evaluation information:
- Attendance Logs
- Intervention activity logs
- Measuring intervention exposure
- Measuring differences in intervention model vs. actual intervention
Once your intervention is finished, you may consider evaluating whether your intervention had an impact on your community of interest. Impact evaluation allows for assessment of the intermediate effects of an intervention. You may consider measuring change in knowledge, attitudes or beliefs, or any other factor that may lead to the desired change in your targeted health outcome. For example, if you are attempting to increase physical activity, you may ask participants to measure their beliefs about the importance of being physically active. Impact evaluations are helpful when the overall outcomes (e.g., increase in activity, decreased television watching, absence of weight gain) are not achieved. Impact evaluation can also be useful in examining social and environmental outcomes of an intervention, for example, an increase in perceived social support. Examples of impact evaluation activities:
- Collecting data on intermediate outcomes (e.g., knowledge, attitudes, beliefs)
- Examining social and environmental changes