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: Shares of staffing agency TrueBlue (NYSE:TBI) fell as much as 26% today, after releasing earnings.

So what: Third quarter revenue grew 2% to $379.5 million, but fell short of the $390.5 million analysts had expected. Earnings were also a little light, coming in at $0.36 per share versus the expected $0.37 per share.

The third quarter earnings miss wasn't good, but what really crushed the stock was fourth quarter earnings guidance of $0.11 to $0.16 per share, when analysts expected $0.22 per share.

Now what: Guidance is often more important than the current earnings report and a big decline in revenue, and earnings in the fourth quarter won't help the stock. Analysts were tripping over themselves downgrading the stock this morning, and the sell-off was on. If the economy picks up, TrueBlue could turn around, but the current trajectory of earnings will keep me from buying on the dip today.

Interested in more info on TrueBlue? Add it to your watchlist by clicking here.

Fool contributor Travis Hoium has no positions in the stocks mentioned above. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings, or follow his CAPS picks at TMFFlushDrawThe Motley Fool has no positions in the stocks mentioned above. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.