What a difference variant recording metrics make.

On Monday, legal consultancy Altman Weil Inc. released a report indicating that 2012’s M&A activity continues the rebound of law firm combinations that began in Q3 2010 and held firm through all of 2011. Altman Weil reported that there have been 14 mergers and acquisitions announced in the U.S. in Q1 2012, which is on pace compared to 16 in Q1 2011 and about 15 over the past six quarters.

The next day, the Hildebrandt Institute released its own report on U.S. law firm M&A activity in Q1 2012, which contained rather divergent statistics. Hildebrandt tracked 20 completed law firm mergers in Q1, which it says represents a 43 percent increase over Q1 2011 (which saw 14 mergers) and a drastic jump compared to Q1 2010 (which saw four mergers).

Like Altman Weil, Hildebrandt says merger activity so far in 2012 is more in line with pre-recessionary levels—33 completed mergers in Q1 2009 and 22 in Q1 2008. Taking it one step further, Hildebrandt says, “[i]t appears that law firm merger activity has been encouraged by signs of economic recovery.”

The difference between the Altman Weil and Hildebrandt reports is that Altman Weil counts mergers when they’re announced instead of when they’re finalized. Additionally, Hildebrandt only includes mergers where the acquired firm has five or more attorneys, while Altman Weil also includes smaller mergers.

All of the law firms Hildebrandt mentions also appear in Altman Weil’s survey, either in their report on Q1 2012 or in its 2011 annual report, Reuters reports. Hildebrandt does not make its full firm list public.

For more, read Reuters.