Add a linear estimate of the purple line
It's nice to have the yellow brick road and know what I need to do to keep from losing my goal, but it would also be nice to have a linear estimate of the purple "average" line or the turquoise swath (maybe only over the last N days?) so you can tell how fast you are actually going.
This is a good idea, and not hard to do. We’re just a little worried about cluttering things. We already sometimes hear complaints that it’s trying to throw too much information at you. We’re willing to be convinced though. We’d love to hear more about how you’d use that info. (Counter-argument: For most people, they’re either just managing to stay on their yellow brick road, or they go way off it. Knowing the rate of the YBR itself usually suffices.)
Nuno Godinho commented
Well, as someone else already said, this could be optional. Besides, you don't even have to draw it on the chart. It would already be nice to have it as an extra value under "Goal stats" next to "cur rate". Think of it as your instant speed.
And besides, that "cur rate" is already shown on the form under the chart next to "make it so" so it's being shown twice. that is clutter ;)
I'm not sure if I understand all of this correctly, but I would like to know the current rate ie. steepness of the thin purple line to compare it to the steepness of the yellow brick road. My page shows "CUR RATE" under Goal Stats, but it's the rate that I set manually, when I set my goal. The purple line shows my actual progress, and I would like to know how it compares to the rate I set.
Player 03 commented
Perhaps you need to make each type of data optional. Give us a set of check boxes we can use: enable the swath while disabling rose-colored dots and the purple line, for example. Then if someone thought the graph was too cluttered, they could turn off one of the data types.
If you are to make a linear regression, you can as well do it directly with the actual data points rather than with already-smoothed stuff.