The latest numbers from the state OMB showed some interesting information regarding taxes, again. Rather than focus on sales tax this time I thought we could branch out into income taxes. Why? Sales tax revenues get the bulk of attention in the media and from me generally and I think branching out is important. Another reason is as the impacts and effects of the oil decline transmit into other sectors more fully, and the state budget cutting starts to fully take effect, we will see other revenues exhibit declines. My interest in the overall forecasting process, if we can call it that, also means we need to branch out into other revenue areas to understand the complete picture of the revenue process. The individual income tax revenue was also almost $20 million short of the forecast in May. With that in mind here is the picture for actual versus forecast individual income tax revenues in North Dakota:
The state released an updated forecast from Moody’s today along with some slides that make little sense (found here). I would go into the details of the forecast but why bother? We have absolutely no insight into the forecast process followed, the assumptions underlying any model relationships, or even a list of variables employed and the time period considered. Seriously, if this were my forecasting class, they would fail.
I did some looking at sales tax revenues. I went back to July of 2009 and stopped the graph at December 2015. I will have a separate post looking at the circumstances after that date with the revision of the forecast and what happened then. These data come from the state OMB Rev-E-News publication released monthly.
This is going to get a bit more technical than many of my other posts. However, I am a big believer that there is no reason to shy away from complexity, particularly when avoiding it sacrifices accuracy. So we are going to discuss forecast performance for sales tax in North Dakota. There are many different ways to evaluate forecasts and the one I will use here is called a tracking signal.
I’ve been saying this for a while now, but I am happy to see somebody else discussing the issue. This Bloomberg article makes excellent points about the issues for North Dakota and several other states experiencing revenue shortfalls.
So I told my forecasting students I would post what I taught them today. I project monthly ND oil prices forward to the end of 2016. The following graph is the result of this process.