If you have trouble forecasting how your remodeling firm will do over the next year, take solace in this: Lots of America's biggest full-service remodeling companies have just as much difficulty.

We reached that conclusion based on an analysis of scores of top full-service companies that have delivered actual and forecast results to our Remodeling 550 project over the past five years. While not comprehensive, the numbers point to huge variations between how much money remodelers thought they'd take in by year's end and what they actually collected.

We could do this because, in each year's Remodeling 550 report, we ask firms to tell us how much remodeling revenue they had collected in the previous year and how much they expected to take in during the current year. So, for instance, in this year's survey we asked for 2015 actual results as well as a forecast for 2016. We've been doing this for years.

For our study, we took the top 100 participants in the full-service part of this year's Remodeling 550 who also took part last year. That way, we could compare their forecast for full-year 2015 (a number they gave us last summer) with their report of how they actually did in 2015 (the number they reported this year). We then checked to see how many of those 100 firms also took part in the 2014 survey; it turned out that 80 did. And for the 2013 survey, we found 60 of those 100 firms. And for 2012, 42 of the 100.

Revenues in this group ranged from about $38 million for the biggest company in 2015 down to about $2 million for the smallest. That puts this cohort solidly in the upper subset of all remodeling firms nationwide, according to research by groups like the Joint Center for Housing Studies (JCHS) at Harvard University.

Given that the forecast we request covers a year that's halfway finished by the time we ask for the information, one would think that remodelers would have a good handle on how things will turn out. And when you look at full-service remodelers collectively, that seems to be the case. This table shows what we found:

Group Total, Forecast GrowthGroup Total, Actual Growth# Surveyed% Beat Forecast

In other words, for 2013 through 2015 the group tended to overestimate its growth by a few percentage points, while for 2012 the end-of-year results turned out better than what the group had thought.

In addition, for three years out of four, somewhere around half of the individual companies surveyed ended up taking in more revenue than they had forecast while the rest were even or finished below forecast. But when you look at how each company did, vast differences turn up. This chart shows the highest and lowest variation between forecast and actual results for each year for 2012 through 2015.

Variations in forecast vs. actual results for selected Remodeling 550 companies, 2012-2015

Of course, while misery may love company, it's no real solace if your numbers diverge wildly from plans. Sometimes that can't be helped; sometimes it can through changes to systems such as WIP (work in progress) accounting. In the end, though, the key to surviving such wild variations looks to be having cash in hand to weather the hard times. That's easier said than done. Still, JCHS data indicates the bigger you are, the less likely it is you'll fail. And keeping your head above water is the first, necessary step toward success.