Average Retail Sales Per Iowa County

Average Retail Sales per Business for Iowa Counties

Keith Greiner

April, 2017

The numerical value of average retail sales per business provides an excellent indication of the strength of a community’s economic position. High values of retail sales per business suggest that the combination of number of business and total amount of local consumer spending have strengths in products that are offered and consumer willingness to purchase those products. The map shown below provides an analysis of the average retail sales per business for Iowa counties for 2015. Counties are divided into four groups, with the darkest values indicating the greatest retail sales per business. The classification and coloration emphasize the top 18 counties because that's where the largest rate of change occurs. This classification method is not the same as equally distributed quartiles.

Average retail sales per business are calculated from Iowa retail sales statistical reports. The reports include quarterly retail sales and quarterly number of businesses. For this analysis, the average is found by summing the quarterly retail sales and dividing by the total annual businesses divided by four. As with all averages, some businesses will have substantially larger values, others will have substantially smaller values. That means this is the average, and is not an indicator of any one business. Averages can be skewed by outlier conditions in which a single business with a very large amount or conversely a single business with a very small value. It is impossible to know the amount of outlier-related skewness that may have occurred.

The four groups are defined as follows:

1. Highest / Darkest -- $592,911 to $774,815
2. Upper -- $380,878 to $533,794
3. Lower -- $227,264 to $344,819
4. Lowest / Lightest -- $115,700 to 224,039

The county with the lowest average is Van Buren, near the lower right-hand corner of the map. The county with the largest average is Dallas (just west of Polk in the central area). Dallas county has an average of $774,815 and Polk county is second, with an average of $735,647. Note that the upper and lower bounds of each group have gaps. That is, the upper bound of of the second group ($533,794) is below the lower bound of the largest group ($592,911). This is because there are only 99 counties in the analysis, and groups are selected from the ranked list of county averages.

Below is a graph of the county averages, sorted in order from the largest, on the left, to the smallest, on the right. In this graph you see the group selection points that are used in the map. The left-most selection point is mid-way in a declining run that occurs between the largest value and the 18th value. The right-most selection point is mid-way between the 19th value and the 99th value. As a result, the map highlights the 18 largest values, presented in groups of nine. A major flex-point occurs between the 18th and 19th values.

Following is a table of the average retail sales per business for Iowa counties, ranked from largest to smallest. This uses the same formatting as other parts of this Excel Statistics Guide where the left column and top row are yellow. This selection of from the spreadsheet is presented in four images below.

A longitudinal analysis of selected counties may be found at this link.

The Excel Statistics Page may be found at this link.