Competitiveness

When you click on the “Analytics” command in DRA 2020, the “Competitiveness” section helps you understand the degree to which the map is competitive.

You’ll see three parts.

Metric

The first part presents the metric:

In contrast to the note in district Statistics that simply counts the number of districts that fall in the 45–55% range, this metric uses a probability distribution to estimate the competitiveness of districts. The tails of that distribution approach zero at 40% and 60%.¹

Rating

The second part presents the rating:

Using historical data and ideal values — an ideally competitive set of districts has a ~75% competitiveness² — the rating normalizes the raw measure to a [0–100] scale where bigger is better.³ The thermometer shows that rating which is further categorized below using a 5-point scale.

Notes

The third part explains what is described above about how competitiveness is evaluated here.

Methodology

To estimate the partisan characteristics of a map, we use:

• A composite of statewide elections, and
• Fractional seat probabilities instead of all-or-nothing accounting, except as noted.

Footnotes

1. For details on the probability function, see this white paper.
2. For example, see the hypothetical “Competitive” plan in A comparison of partisan-gerrymandering measures (Warrington, 2019).
3. For more details and context, see Ratings: Deep Dive.