A glance at NRF holiday forecasting

NEW YORK (AP) -- It's not even Halloween yet, but once again a slew of forecasters are out with sales predictions for the all-important holiday shopping season.

Economists carefully study the numbers because they're an important gauge for merchants that depend on the period for up to 40 percent of their annual sales. But forecasting holiday sales is tricky. That's because there are lots of variables that can quickly make shoppers open or shut their wallets from how the stock market moves to Mother Nature. A wave of unseasonably warm weather, for example, can depress shoppers' appetite for cold-weather boots and coats.

Here are the original holiday forecasts along with the actual sales changes for the previous five years from the widely watched group The National Retail Federation, the nation's largest retail trade group. For the previous three years, the group's initial forecasts ended up being too cautious. For 2007 and 2008 NRF's predictions turned out to be too rosy.

The numbers below are the original holiday sales percent changes before NRF this year revised the figures to adjust to a broader definition of retail sales that includes online sales and business from auto parts stores.

THE NRF HOLIDAY FORECAST ACTUAL HOLIDAY SALES CHANGE (before revisions)

2011: +2.8 percent +4.1 percent

2010: +2.3 percent +5.2 percent

2009: -1 percent -0.4 percent

2008: +2.2 percent -4.4 percent

2007: +4 percent +1.8 percent