Counties and other units of local government are currently in the process of drafting budgets for the upcoming year. As with all budgets, county budgeting is based on projections and estimates: how much money will be generated from taxes and fees, how much will be received from the state, how much will be spent, etc.
While there are similarities between county and municipal budgeting, a major difference is the sales tax. Unlike municipalities, counties have the option of imposing a 0.5% sales tax. The sales tax is "piggybacked" on the state sales tax, meaning the same items are taxable. The tax is administered by the Wisconsin Department of Revenue (DOR), then distributed to individual counties (DOR retains 1.75% of total county sales tax collections as an administrative fee).
These sales tax estimates for 2018 are reported using three numbers. The "mid" estimate is calculated based on average sales tax growth in the county over the past several years and estimated statewide growth. However, in most counties, collections are somewhat volatile from year to year, making it difficult to estimate future revenues. In other words, there is a "margin of error" associated with the "mid" estimate. The "low" and "high" estimates reflect this forecasting error. Effectively, these two numbers reflect a band within which revenues are expected to fall. Statistically, it is not likely that revenues will fall below the "low" figure or above the "high" figure.
These numbers should be viewed strictly as a starting point from which counties can consider unique factors that may impact their individual tax collections. Data analysis was provided by the Wisconsin