Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: It's another down day for the stock market, and investors (those who haven't already gone away in May, that is) are taking out their frustrations on companies that disappointed this earnings season -- companies such as Employers Holdings (NYSE: EIG), which last night reported earning $0.06 less per share than it was supposed to.

So what: The workers'-comp "specialist" (EH's words, not mine) reported $0.21 per share in profit for Q1 2011, versus consensus expectations of $0.27 up on Wall Street. Even worse, that was 45% less than the company earned a year ago.

Now what: Even worse than that, EH confirmed that its calendar-year combined ratio (the amount of claims money it pays out, relative to the amount of premium money it collects) currently stands at 116.9%. As a general rule, anything over 100% is bad news, and lower is better. Industry icon Berkshire Hathaway (NYSE: BRK-A)(NYSE: BRK-B), for example, had a combined ratio of 92.2% at last report.

Which kind of makes you wonder: If you're investing in insurers at all, why not just buy the best? Sure, Berkshire costs a little more than Employers Holdings -- 15 times earnings as opposed to 11. But judging from its combined ratio, it's clearly a better operator. As a bonus, you can tell your friends and neighbors: "Buffett? Oh, yeah. He works for me."

Want more information on Employers Holdings? Add it to your watchlist.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.