Patent litigation is once again on the rise after what now appears to be an only temporary dip in 2014.

There were 1,443 patent litigation filings in the first quarter this year, according to an analysis by Unified Patents, which hand sorts out duplicate filings. Unified is an advocacy organization with the stated goal of deterring frivolous patent litigation. Those numbers were verified, and correspond closely with the federal district court patent filings in the first quarter reported by Bloomberg Law .

If present trends continue, there would be an estimated 5772 filings for calendar 2015, a 15% increase over the previous year, when Unified reported there were 5,002 suits.

Patent litigation filings have been up and down in recent years, with a record high of more than 6,000 filings in 2013. In 2014, however, patent litigation declined slightly for a variety of reasons.

For instance, the U.S. Supreme Court, inAlice v CLS Corp., waded back into the longstanding question of whether an abstract idea is patentable, holding that a computer program created simply to apply an “abstract idea” – and add nothing else – does not carry the necessary originality for a patent. Some lawyers believed the decision would curb the number of patent claims, but that now appears unlikely.

“What we saw afterAlicewas a definite drop, and then a rebound” in 2015, said James Bessen, a lecturer in Intellectual Property and Economics at Boston University School of Law.

Bessen said he believesAlicecreated uncertainty about what would be valid under the law, but said the dip in district court filings could also be a result of the fact that the U.S. Patent and Trademark Office’s launched a new venue to challenge suits.

The Patent Trial and Appeal Board (PTAB), an administrative law panel established within the USPTO by the 2012 America Invents Act, allows defendants to ask for a pre-litigation review of a patent’s eligibility. If the patent is declared invalid, a claim is terminated. Activity at the PTAB doubled in 2014, meaning “a lot of cases never got to litigation,” according to Bessen.

Unified Patents also tracks this information and found PTAB challenges were brought on 45 percent of all patent litigation in 2014. In contrast, PTAB challenges were brought on only 23 percent in the first quarter of 2015.

Bessen suggested the decline in PTAB challenges can be attributed to the USPTO ‘s narrow interpretation of theAlicedecision, which has led to a drop in the number of challenges it is seeing. “Software patents generally have taken no hit at all,” says Bessen, of the PTAB reviews. “[Business method] patents definitely have, but that represents only a few hundred patents.”

Illustration by FutUndBeidl (Flickr/Creative Commons)