In early 2013, after watching for a long time how EMS oversight and provider agencies completely mis-use MPDS, I started a little project to collect data. You can read it here, including the objectives, inclusion/exclusion criteria, methodology and findings.
In short, I collected some data to demonstrate some possibilities in fine-tuning how we can apply MPDS to the field so there is less frustrating discrepancy between what the reporting parties tell dispatch and what we actually find on scene.
The most common problem with the administration of MPDS is that all these EMS oversight agencies turn it into a revenue-generation tool based on response time compliance. In fact, MPDS is NOT about response times; it is about dispatching the appropriate resources.