General Motors begins shipping replacement parts. Is the worst over?

General Motors has begun shipping the parts needed to repair Chevrolet, Pontiac, and Saturn models affected by GM's high-profile "Switchgate" recall. That's good news for the company's marketing staff, who've been putting in long hours to minimize the recall's damage to GM's image and that of its four car brands.

The better news, however, is that the worst of GM's troubles could be behind it -- at least according to a public opinion survey carried out by market research firm YouGov.

Every weekday, YouGov polls 5,000 U.S. residents, asking them to assign scores to various companies, based on their personal opinions. The scores can range from -100 (a very negative opinion of the company) to 100 (a very positive opinion). YouGov then tallies those scores to create what they call a "BrandIndex", which gauges how well (or how poorly) a company is perceived by consumers.

On average, the auto industry maintains a fairly low BrandIndex score, typically hovering in the "10" range, or slightly positive territory. Some auto brands score well above that -- as Ford recently did -- but others rank well below -- as Jeep did last summer, following Chrysler's refusal to recall flawed Grand Cherokee and Liberty models.

As you'll see from YouGov's most recent stats, GM's BrandIndex score began to nosedive right around the time that the first batch of Switchgate recalls was announced in February. Over the next two months, GM's score continued to plummet, hitting a low of -33 last week. (Interestingly, one of the vehicle brands affected by the recall, Chevrolet, didn't experience anything like that kind of drop.)

Then something curious happened: during the past two weeks, public opinion of GM began to improve. At -26, the company's BrandIndex score is still in negative territory, but YouGov's polling seems to indicate slow, steady recovery for both the GM and Chevrolet brands.

What's behind the rebound? It's difficult to say. However, we have three reasonably good hunches:

1. Mary Barra: Barra has been front and center during the recall process, and she's got several things going for her. For starters, she's well-liked: when the new CEO's appointment was announced in December, the media and the public seemed very enthusiastic. Also, she's new: it's hard to heap blame on someone for the problems left by her predecessors. And just as importantly, she's articulate and open. In situations like this, creating an atmosphere of clarity and transparency shows that you and/or your company are making an effort to resolve things in good faith.

2. The simplicity of the recall problem: GM's ignition switch flaw is easy for most people to understand. It makes sense: put too much pressure on the switch, and it can turn off. Compare that to the mysteries and confusion surrounding the Toyota/Lexus recalls of 2010, when every pundit on the planet had a new idea about what was causing unintended acceleration in some vehicles. Complicating matters were (a) Toyota's lack of transparency, and (b) several hoaxes and false claims related to the recall. The simplicity of GM's problem doesn't excuse its 13-year delay in fixing it, but it does minimize the kind of hysteria that put Toyota's sales in the tank.

3. Spring shopping: in most of the country, winter is on its way out, and shoppers have descended on showrooms for the traditionally robust spring buying season. That puts consumers in contact with GM cars and, more importantly, salespeople. Those face-to-face interactions may have thawed customers' opinions about the automaker.