Analysts retroactively downgrading stocks


Jim Cramer frequently talks about the importance of flexibility in investing: as he paraphrases John Kerry, you have to be "Willing to vote for a stock...before you vote against it." However, saying that you had a different opinion on a stock after the fact isn't being flexible: It's lying. It's the Wall Street equivalent of saying you knew the Red Sox were gonna pull it off down 3-0 in the 2004 American League Division Series.

Yet according to research by Alexander Ljungqvist, Christopher Malloy, and Felicia Marston, it appears that analysts may be doing just that: changing their sentiment retroactively to appear more prescient than they really were:

Comparing two snapshots of the entire historical I/B/E/S database of research analyst stock recommendations, taken in 2002 and 2004 but each covering the same time period 1993-2002, we identify tens of thousands of changes which collectively call into question the principle of replicability of empirical research. The changes are of four types: 1) The non-random removal of 19,904 analyst names from historic recommendations ("anonymizations"); 2) the addition of 19,204 new records that were not previously part of the database; 3) the removal of 4,923 records that had been in the data; and 4) alterations to 10,698 historical recommendation levels. In total, we document 54,729 ex post changes to a database originally containing 280,463 observations.

According to the Social Science Statistics blog, the changes made caused analysts to appear more cautious and more accurate. While this certainly has the makings of an enormous scandal (Much bigger than options-backdating, in my opinion), the larger question is this: Why would you listen to analysts anyway? Numerous studies, including those discussed in David Dreman's classic book Contrarian Investment Strategies have shown that following the analysts will lose you money.

[Found via Megan McCardle]

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