With the Super Bowl over and pitchers and catchers reporting in a week, baseball season is finally in sight. For me one of the most interesting parts of the offseason is the Fans projections. I think they offer an incredible collection of information on what the crowd thinks about the coming year. As the offseason transition to spring training I wanted to take stock of these projections.
Last week Tango released the Marcel projections, which give a perfect baseline for comparison for the fan projections (you can also view the Marcels here at FanGraphs). Marcel takes three years of past performance, weighting more recent performances more heavily, regresses towards mean and then applies a simple aging factor to come up with its projections. It is designed as the minimum projection system not taking into account park factors, minor league data or other more complicated inputs. By comparing the fans to it we can get a nice picture of what they are thinking.
Last year we saw that the fans were relatively optimistic — by about half a win — but it turns out they still did fairly well. Today I will look at the position players and break up the comparison into two parts: projection for playing time and projection for wOBA. I am just looking at players with 15 ballots and grouping all ballots, not separating by favorite team ballots. In all cases the Marcel projections are on the x-axis and fans on the y-axis. I indicate the Marcel equals fans with the red line (this is not the line of best fit). Thus points below-and-to-the-right of the line represent players projected higher by Marcel, and those above-and-to-the-left those projected higher by the fans. Here is projected PAs.
There is an interesting triangle pattern. There is considerable variation in the fan-projected PAs for the group of players with low Marcel-projected PA. At the top-left of this triangle are players with high fan-projected PAs and low-Marcel projected PAs. I think they fall into two categories: those whose health the fans are optimistic about (Jacoby Ellsbury) and those at the top of a depth chart for the first time (Mike Stanton). For players with a high Marcel PA projection the fans are in agreement, the point of the triangle at the top right.
With few exceptions the fans are much more generous with playing time than Marcel. Marcel regresses playing time heavily, something that the fans seem not inclined to do. Part of this might be selection bias. The players graphed are just those with over 15 ballots. Maybe fans are just not interested in projecting players who lost their starting jobs (who would fall below the red line). Overall I trust the fans with their better depth-chart knowledge, but want some of Marcel’s regression. So I might take 85% of the fans’ PA projections, or something like that.
Now to wOBA.
Here there is much more agreement. The relationship is a very tight linear fit, with the fans broadly agreeing with Marcel on wOBA. But there is still systematic deviation from the x=y line. There is a trend for fans to be lower on below-average players and higher on above-average players. I think this also stems from Marcel’s regressing. Below-average performance is going to be regressed up toward average, and above-average performance is going to be regressed down towards average. If the fans are less likely to regress we will see this pattern. For average players the fans are also higher than Marcel, so even on top of the lack of regression to the mean it looks like the fans are optimistic. Here I am a little more likely to trust Marcel over the fans.
Tomorrow I will look at pitchers.