Steve Levitt is an incredibly smart guy (he has a Clark Medal, the prize for best economist under 40, to prove it) and, according to the people I know who know him, a very nice guy. Freakonomics is fun to read, and I liked it enough to use it for a seminar I taught last summer.
A reason the book is so much fun is that it is provocative, and challenges us to think about things from perspectives we had not before considered. It asks why drug dealers live with their mothers; whether Roe v Wade was responsible for the falling crime rate in the 1990s; whether Sumo Wrestlers cheat; and whether real estate agents shirk.
Levitt sets up the real estate agent-house seller relationship as a classical principal-agent problem: the agent is like anyone else: he has an incentive to do as little work as possible in exchange for as much commission as possible. Therefore, Levitt conjectures that real estate agents have an incentive to get sellers to take the first offer they receive from buyers. Because commissions are based on the entire price of the house, the fact of a sale gives agents a large benefit. If the seller refuses an offer, the agent has to do more work, but gets very little added compensation. For example, if there is a $490,000 offer on a house that could ultimately sell for $500,000, and the agent gets a 1.5 percent cut, from the standpoint of the agent, the benefit of waiting is only $150. The agent will almost certainly have to do a lot more work for the $150, and so has an incentive to encourage the buyer to take the $490k.
This would be a powerful argument for an incentive problem if agents were playing a one-shot game. But they are not--they are playing a repeated game. Agents rely on listings to make money, and listings come from referrals. Agents--good ones anyway--have an incentive to make sellers very happy, because happy sellers drive future business.
So now let's get to the evidence that Levitt provides to show that agents shirk: he shows that agents leave their own
houses on the market longer and sell them for higher prices than the houses that they sell for others. This is an interesting fact, but is not necessarily explained by agents' shirking. Rather, it could be that the houses agents own themselves are different in unobserved characteristics from the houses that they sell to others. Or it could be that agents are different as human beings--they are more risk taking, and more entrepreneurial. For all we know, sellers ignore the advice of their agents and sell more quickly than they should, because they are relieved at the prospect of a sale and don't care so much about the marginal benefit they
would get for waiting. In order to disentangle this, we would need to know something about the unobserved characteristics of people who become real estate agents--and of people who don't.
Full disclosure: while I was writing my dissertation in the late 1980s, I worked doing research for the Wisconsin Realtors Association. I had fun while I was there. Believe me, the Realtors are
different with respect to their attitude toward risk taking from the rest of us.