# June 2020 probabilistic senate prediction competition

Consider the following senate races:

Alabama
Arizona (special)
Georgia
Georgia (special)
Iowa
Kansas
Kentucky
Maine
Michigan
Montana
North Carolina

The goal is for each race to assign a value, P(D), between 0 and 1 that represents the probability that a Democrat wins the seat, the value P® = 1 - P(D), that represents that a Republican wins the seat is implied by P(D).

Note: the Alaska race is between an incumbent Republican (Sullivan) and a Democratic Party backed independent (Al Gross). For the purposes of this contest I’m considering Gross a Democrat, which I’m sure would bother him to no end.

Also note: there are two senate races in Georgia this year. Be sure to mark which one is the special election.

Entries will be submitted by posting in this thread. The most recent post by a user with a timestamp on or before June 30, 11:59:59 PM CT will be that user’s entry (i.e. you can change your entry until the end of June).

After the election results are known, I will compute the Brier score for each entry. Participants will be ranked by Brier score where lowest is best.

Here’s my prediction market derived sample entry that will almost certainly update by the end of the month.

AK 16.2%
AL 5.5%
AZ* 94.5%
CO 96.2%
GA 34.7%
GA* 35.1%
IA 47.0%
KS 17.9%
KY 9.7%
ME 75.1%
MI 92.3%
MT 51.5%
NC 62.7%

I only know about NC . I would predict 40%

Here’s mine:

AK 18%
AL 4%
AZ* 91%
CO 85%
GA 43%
GA* 27%
IA 50%
KS 13%
KY 10%
ME 88%
MI 93%
MT 59%
NC 72%

Your failure to properly enter is noted. You have until the end of June 30th to rectify that. Alternatively, feel free to enjoy last place.

Is there a prize for last place? I hope so.

Not great confidence in these, but my best shot.

One week remains to get those entries in.

Reminder: the deadline to submit or update an entry in Tuesday 11:59:59 PM CT.

Here’s an update to mine. Iowa is ever so slightly leaning blue now in my prediction market based model.

Race P(D)
AK 15.2%
AL 7.4%
AZ* 94.3%
CO 96.6%
GA 34.0%
GA* 35.4%
IA 52.0%
KS 18.3%
KY 8.7%
ME 76.0%
MI 93.7%
MT 57.8%
NC 64.6%

There’s about 12 hours left to submit/update entries.

My latest update…

Race P(D)
AK 18.4%
AL 8.2%
AZ* 93.8%
CO 95.5%
GA 34.5%
GA* 33.2%
IA 51.2%
KS 18.2%
KY 8.7%
ME 76.8%
MI 92.7%
MT 60.4%
NC 65.0%