Numbers are funny things. Take Monday's report from the National Association of Home Builders, in cooperation with Wells Fargo, for example.

Fans of homebuilder stocks like Toll Bros. (NYSE: TOL) and Pulte (NYSE: PHM) will no doubt be thrilled to learn of the recent, sharp upturn in sentiment among the nation's homebuilders. The NAHB/WFC poll asks homebuilders three separate questions, then averages the results into something it calls the "Housing Market Index" or "HMI." All three component indices, and the HMI itself, rose sharply in May -- up three points, or nearly 16% between April and May. And this was on the heels of a similar three-point rise from March to April. Combined, the index is up a startling 37% over the past two months. Check out each of the three components:

Source: Author's graph using NAHB/WFC data.

But ... this one goes to 11
But here's the thing: What you're looking at up above is just one small slice of the scale. In fact, the full HMI runs not from 0 to 35, but from 0 to 100. In order to be considered "bullish," you need numbers in the 50s -- and we haven't been there for quite some time. The last time the blue line up above (actual sales trends) touched 50s territory was May 2006. The red line (expectations for six months out) showed homebuilders abandoning hope of an imminent recovery about a year later, in March 2007. And as for actual foot traffic -- "boots in the atrium," as it were -- those started dwindling as far back as October 2005.

Too soon, too soon
As for how things stand today, well, the chart up above still shows actual foot traffic as the weakest indicator of the three, while the "pipe dream index" looks strongest. (Which may explain why homebuilders like Ryland (NYSE: RYL), MDC Holdings (NYSE: MDC), and Hovnanian (NYSE: HOV) have been observed bulking up on their land holdings, in anticipation of a recovery.) Meanwhile, Home Depot (NYSE: HD) and Lowe's (NYSE: LOW) are giving out mixed signals on the year ahead (Big Orange sounds optimistic, but Lowe's guided below Street expectations).

Call me a skeptic, but I wouldn't lay down a deposit on housing's recovery just yet.

Take the Foolish Rorschach test. Do you see something different in today's chart? Tell us about it below.

Fool contributor Rich Smith owns shares of MDC Holdings. Rich is not a licensed economist, but he plays one on the Web. Check out his latest stock recommendations on Motley Fool CAPS. Home Depot and Lowe's are both Motley Fool Inside Value selections and MDC Holdings is a Motley Fool Hidden Gems pick. The Motley Fool has a disclosure policy.