Public company audit deficiencies fell for a second consecutive year in 2015, but still cropped up in nearly one-third of all inspected audits, according to a new analysis.

Valuation and consulting firm Acuitas published its annual analysis of audit inspection reports issued by the Public Company Accounting Oversight Board, finding inspectors flagged deficiencies in 31.6 percent of all audits inspected in 2015. That was a decline from 39.2 percent in 2014 and 42.9 percent in 2013, the firm said.

The analysis also revealed 31 percent of all audit deficiencies stemmed from problems with fair value measurements and impairments, many of those arising as a result of a surge in business combination activity. Of the fair-value-related deficiencies recorded in 2015, 68 percent arose from business combinations, such as mergers or acquisitions, up from 56 percent the year before.

The PCAOB has called out audit errors arising from estimates, including fair value measurements, as an area of audit that requires some attention and guidance. The board has been working for several years on upgrading its standards in that area, issuing a proposal for new guidance in June. The comment period for that proposal ended Aug. 31. The PCAOB also calls out business combinations as a factor that adds risk to the typical financial statement audit.

Acuitas says in its report that root causes of audit failures tied to fair value measurements and impairments tend to arise from failures to assess audit risks, to test internal controls, and to test assumptions underlying asserted financial information. Fair-value-related audit deficiencies tend to involve problems with pricing, failures to test, disclosures, risk assessments, financial projections and assumptions, and other-than-temporary impairments.

The Acuitas analysis also finds that the trend in fair-value-related audit deficiencies is similar the trend in audit deficiencies as a whole. Deficiencies related to fair value peaked at nearly half of all audit deficiencies in 2010 and have tapered in the years since.

“It’s apparent that the number of audit deficiencies remains high, owing to a surge in deal-making activity,” said Mark Zyla, managing director at Acuitas. “But we are seeing industry and accounting firm leaders committing to more quality control measures and ensuring due professional care, hence the decline.”