My semester paper analyzed the Illinois Prarie District Public Library budget. Specifically the question: Are the renovation plans of Roanoke Branch library the best use of district funds and are they supported by academic sources, budgetary research and demographic analysis?  I will spare you the 14 page PDF and focus on the the geospatial methodology section:

A demographic review of the population within the libraries district is important to understand the patrons served. The IPDPL has assumed a growing population for the last few decades. Based on population projections district staff has operated under the assumption that they serve over 21,000 patrons. Seeing that the district is comprised of a very specific set of township county subdivisions, population estimates are fairly easily attainable. According to Esri Inc. demographic data models and availability the IPDPL serves an estimated population of 22,392 in 2017 (Esri). This coordinates surprisingly well with the library director’s assumptions and corroborates planning for future expansion.

Natural comparisons would be made between Germantown Hills branch location and the Roanoke facility. Data science gives us the opportunity to look at facts and not just anecdotes. In reality, aside from sharing a highway, the two locations are not very similar. Population within a 10-minute drive of the Germantown Hills branch is 16,660 while a 10-minute drive from the Roanoke Branch only brings in 3,872 potential visitors. Likewise, median household income is also skewed towards Germantown Hills which is $82,183 in the same 10-minute drive. Roanoke is almost a full $20,000 less with their median income at $62,301(Esri). Figure 9 shows a map of the five (red) and ten-minute (green) drives from the Roanoke and Germantown Hills locations within the boundary of the IPDPL with the other three locations marked as a green star.

However, the geographic coverage of this drive time analysis is a full third of the entire IPDPL region. Given the previous discussion on community benefits of collaboration spaces, this dissimilar nature should not disallow Roanoke from benefiting from a newly renovated library branch. In Fact, quite the opposite is true.

In addition to demographic study, the tax base analysis was in order for this research to project potential future revenue for the district library. The Illinois Prairie District Public Library levies a 0.256% on the equalized assessed valueation for taxpayers. For example, a homeowner in the district with a home with a fair market value of $300,000 will pay taxes on 1/3 of that or $100,000. The IPDPL then takes 0.256% of that or $256 of a resident’s tax bill goes to the district(IDOR). Data estimates of housing values for the district can take these calculations into considerations and give a reasonable valuation for future revenue from the county tax levy alone.

Considering the IPDPL tax rates and projections of housing values Table 1 shows the estimation of incoming revenue through the year 2022.  When comparing the Esri Housing value data to the existing tax levy collected in 2017 of $1,280,974.11 the calculated difference was applied back to those 2022 numbers resulting in an estimated adjusted total of $1.5 million dollars to be levied by 2022 assuming a moderate increase of property values.

The excel spreahsheet that calculated the adjustment has been given to the Library Director.

I have also Attached the demographic Reports PDF from Esri: Demographic_and_Income_Profile   Executive_Summary   Housing_Profile

And My Final Report.

As an FYI, my research  wholeheartedly reccomends the renovation.