Logic models (similar to program theory) are popular in evaluation. The presumption is that programs or interventions can be depicted in a linear input output schema, simplistically depicted as:
This simple example can be illustrated by using this model to evaluate how an information fair on reproductive health contributes to the prevention of unwanted pregnancies.
The inputs are the money, labour, and facilities needed to produce the information fair.
The activity is organizing and presenting the information fair.
The output is that some people attend the info fair.
The outcome is that some of those who attend the info act on the information provided.
The impact is that unwanted pregnancies are reduced.The idea is that each step in this causal chain can be evaluated.Did the inputs (money etc.) really produce the intervention?
And did the activities produce the output (an informed audience)?
Did the output produce the outcome (how many attendees acted on the information)?
To measure the impacts, public health statistics could be used.
A quick overview of logic models is provided on the Audience Dialogue website. One of the best online resources for developing and using logic models is Kellogg Foundation’s Logic Model Development Guide, and loads of visual images of logic models are available, and aboriginal logic models have also been developed.
See also Usable Knowledge’s short tutorial on creating a logic model.
And readIan David Moss’ In Defense of Logic Models, which is probably the most reasoned response to many of the criticisms… take a look at the comments to his blog post as they extend the discussion nicely.