Let's set a basic premise. This is being written in very general terms. The approach can differ based on the subject matter of the patent(s) under review. The subject matter of the patent often dictates the form of analysis undertaken. For example, at the most basic level, mechanical-based patents often focus on structural improvements that function more effectively; software-based patents often relate to efficiency improvements introduced through some novel logic or process; and chemical patents often highlight new material properties or unexpected applications. The trick is often to quickly identify the one or two specific features that are not readily apparent in the prior art in the relevant time period. The prosecution history may help identify that for you based on the stated reason for allowance. If the prosecution history is not helpful, sometimes the specific feature is easily identified because the claims recite a "new" term of art in the claims. The term may be new, but the feature may be well-known by another name. To locate that feature in the technical field, you'll need to look for variants of the feature in the prior art.
Sometimes the feature is well-known, but is not well-discussed along with other concepts recited in the claims. In that situation, the focus usually revolves around seeking information about the feature in different contexts to find the contexts that best match the other recited concepts in claims.
There are other searching techniques used. The main point is the need to identify the specific feature(s) that will be critical for the invalidity analysis. Once that is accomplished, you can catalog prior art that reaches all recited concepts in the claims, along with the specific feature. The difficultly often lies in figuring out what the state of the art is in a certain time period, what features were discussed in combination with each other, and how different features were described to solve specific problems.
Some might argue that this cuts close to hindsight-based review. I would disagree because until you know the state of the art, who the players were, and what the industry focus was, you can't tell an effective story. We decided to use software to arrange the story elements much like a screen writer uses software to keep track of characters, settings and plot lines. In the end, this is all about the story you are telling. Your first cut at your invalidity contentions lays out all possible story paths. As you move towards summary judgment and expert reports the story is refined.
The problem we see in Court decisions is that some of the possible story paths may be discarded if you don't disclose them early enough in the case. We've created a system that not only helps preserve all possible story paths, it can also help you craft the most effective story while you prepare for trial. We offer a 15 day trial to see how this system performs. Let us know if you're interested in a new approach.