Recent posts clearly place me in the camp of “critic” for the sales tax data from Grand Forks. Criticism can be important because it encourages us to make things better, to improve upon the inadequate. With that in mind I offer up some alternatives that might be better than the current system. If we need to remove some of the “ups-and-downs” of the data, for whatever reason, let’s try to keep the some of the features of the data that keep us in the realm of informing policy. This first graph is for a long period of time and may be a bit difficult to see.
The green smoothed line is there and offers a view of the trend without all the variation. I also made one for a shorter time period.
You can see that there is still some of the variation in the data, there are “ups-and-downs”, but the trend is still there without being a sum of the last twelve months. The readings from the smoothed series are much more “accurate” in the sense that they are not an alternative calculation, but the trends are still there as well. I think my smoothed measures are much less of a distortion and better inform policy than what is used currently.
