If someone wanted some fun with AOP here is a nice idea. Each node can track which rule and which part of the rule it was originaly from. Use AOP to log the number of propations in a node and then produce a heat map output, intially as a scale, you can click on a colour and it shows the rules in that range. Further to that the rules themsleves should have the patterns and even the indivual constraints annotated with a background constraint indicating their usage rate. If anyone gives this a go, please do use SWT so we can embed it in Eclipse, but a GWT equivalent would be good too :) This could be extrapolated further with drill downs, recording the heatmap over time, and with a break down for which fact or field changes causes what usage rates. Mark