My understanding is that there are a few reasons why it can be a bad idea. First of all, prior art seems to be taken more seriously during the re-examinations that happen during lawsuits. If the prior art is presented beforehand and the patent is granted anyway, then that avenue is closed off. In addition, it gives the patent filer more of a chance to tweak their patent to try to work around the prior art and re-file it (often several times) until it gets granted. So you want to only present prior art during the phase of examination during which it's taken the most seriously and when the patent filer doesn't have an opportunity to game the process by refiling over and over again, which usually means waiting until it comes to trial.

Secondly, patent attorneys don't like their clients doing any sort of search of/reading of any patents that could potentially affect their work. If you're found to have knowingly violated a patent, the damages are far greater than if you did it unknowingly. Submitting prior art to try to get a patent thrown out before it's granted would necessarily require researching and reading up on those very patents, so if the patent didn't get thrown out and you were eventually sued for infringing it, you'd be in much, much bigger trouble. Presumably the people who have the incentive and knowledge to bring up that prior art are likely to be involved in the same segment of the industry, which puts them in an awkward position: do you try to get the patent thrown out ahead of time, and be in serious trouble if you fail, or do you hope you don't end up at trial but keep the prior art in your back pocket in case you do?

Perhaps big companies could have a dedicated legal arm to research and challenge such patents at arms-length from their developers and/or keep their developers aware of potential minefields, but for smaller companies you'd be better off avoiding patent searches or research altogether.

That's fairly paradoxical given that patents are supposed to further innovation by giving people an incentive to disclose their inventions, but that's what the software patenting world has come to . . .

> Isn't there some legal strategy reason why challenging patents is a bad idea? Like, the due process involved is minimal, and having survived a challenge, the facts behind the challenge strengthen the patent in court?

At the margin that's indeed a concern.

Many patent attorneys think, however, that --

A) On average you're likely to get a better take on patentability from an examiner, who has at least some background in the technology and who doesn't have a presumption of validity to overcome;

B) Suppose you have prior art that you think invalidates the claims of a patent application, but you withhold it from the patent applicant in hopes of using it later on as a defense in infringement litigation. The patent owner's trial counsel is likely to argue to the jury that your actions then speak louder than your words now. "If the prior art was so great," counsel will argue, "why didn't they give it to the patent applicant to be forwarded to the patent examiner? They're just trying to pull the wool over your eyes, and making you do extra work evaluating this supposedly-great prior art reference, when they could have saved you the trouble by having the examiner look at it in the first place."

Does the latter argument actually work in court? Is it the expectation of courts that people will continually monitor patent applications looking for things to invalidate?

That's how I've always understood it. The examiner is supposed to check for prior art, but (1) it's hard and (2) that cuts into revenue. The fallback mechanism has always been the patent appeal - generally the appellant has an interest in voiding the patent or some of its claims for business reasons, but there's no reason you have to.

So yes, it's the expectation of the courts that people will continually monitor granted patents and appeal them as necessary. And I guess patent applications as well.

> So yes, it's the expectation of the courts that people will continually monitor granted patents and appeal them as necessary.

I dunno about that. My sense is that a patent owner's counsel would not try to argue that the accused infringer had a general duty to monitor pending applications or issued patents. The argument would be, instead, that the circumstances suggest that the prior art in question wasn't so good after all.

Keep in mind that jurors are usually non-technical. Therefore, patent litigators try hard to find understandable indirect- or circumstantial evidence that can get the message across to the jurors. EXAMPLE: If someone walks into the courtroom in a dripping-wet raincoat, that's indirect evidence of rain. EXAMPLE: Widespread imitation of an invention, or praise for it, is regarded as indirect evidence of nonobviousness.

In this hypothetical, the patent owner's counsel argues that the defendant's failure to bring the supposedly-killer prior art to the attention of the patent examiner is indirect evidence. Of what? That the prior art wasn't so good after all, and that the defendant is trying to put one over on the jurors.

Wow. This goes to show you how easy it is to overestimate what you know - my patent experience is all about translating stuff from German (or French) into English, so now that I think about it, all the appeal documentation I've ever seen has been before the European patent appeals court. The thought of defending a patent in front of a "jury of your peers" is frankly something I never even thought of.

The insidiousness of ignorance...

The way I've heard it, patent examiners must meet high quotas. Rejecting too many applications and fighting the inevitable appeals (which isn't counted equally as useful work for some reason, possibly because it doesn't bring USPTO very much revenue) can cost them their jobs, while there are basically no consequences (at least not for themselves or USPTO) for rubber-stamping applications that should rightfully be rejected. If your prior art can only be seriously considered one time, that's not who you want doing it, however qualified they might be.

There is if I remember correctly: if the entity applying for a patent places his patent on peer to patent for public review and it passes, I think the process for acquiring the patent will be much faster vs going the traditional route

IANAL