I was trolling though recent opinions in search of a blog post topic (you're welcome) when I stumbled upon a recent Markman order discussing disclaimer. Now normally Markman orders aren't the most fecund ground for a post. But seeing the pro forma language about how prosecution history disclaimer required a "clear and unmistakable" disavowal I had to ask myself—"do they ever find that?"
The answer, is "not really, no." Frequent readers will know that I normally do the last 10 opinions, because I have forgotten all the math I used to know and its easy to calculate the percentages. Here though, I looked through the last 10 and was still at 0. So I pressed on until we hit a winner at the 15th oldest decision. For those with calculators, that's a 6.7% success rate.
What really surprised me about this number was that I only had to go back 2 months to find 15 cases where a defendant had alleged disclaimer, given the abysmal success rate. I'll update this post the next time we get a winner to see if we can piece together a unified theory of what makes these arguments work.
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