90 seconds to Boston

UPDATED! The analysis has been updated. The latest analysis is available here: http://boston-qualifier-stats.blogspot.ca/2015/08/santa-rosa-marathon-sways-boston-cutoff.html

With 22 of the top 25 feeder marathons complete, the current trend for the 2016 Boston Marathon Cutoff is 90 seconds. (or 91 if you're a pessimist).

Only 3 more left (Grandma's, Santa Rosa and Lehigh).

The Caveats:
The analysis assumes a lot of assumptions. I have outlined the objective and methodology on this page. Basically, I look at the number of people who qualified for the 2015 race, using the "feeder marathons". To qualify for the 2015 race, participants needed a BQ minus 1m2s. These races were all run last year. I then look at the same races for this year, and see how many people would qualify using the same cutoff.  If fewer people qualify, then I decrease to cutoff (make it easier to qualify), until the same number of people qualify as did last year. Conversely, if more people make the 1m2s cutoff than last year, I increase the cutoff (making it harder to qualify) until the same number of people qualify.


Table 1: Year vs Year, By Marathon

	2015 Qualifying Year				2016 Qualifying Year
Marathon	Finishers	BQ	BQ2015	BQ2015%	Finishers	BQ	BQ2015	BQ2015%
Big Cottonwood	1,308	262	244	19 %	1,527	284	252	17 %
Erie	978	312	280	29 %	959	317	289	30 %
Berlin	36,122	5,769	5,455	15 %	29,027	4,530	4,308	15 %
St. George	5,818	1,198	1,137	20 %	5,806	997	939	16 %
Twin Cities	8,855	1,010	953	11 %	8,853	1,041	967	11 %
Portland	6,945	504	470	7 %	6,429	429	395	6 %
Chicago	38,854	3,527	3,314	9 %	40,581	4,004	3,762	9 %
Steamtown	2,165	377	359	17 %	2,184	431	408	19 %
Columbus	5,523	611	561	10 %	5,445	620	581	11 %
Toronto Waterfront	3,604	487	453	13 %	3,971	654	601	15 %
Baystate	1,304	301	271	21 %	1,531	378	350	23 %
Marine Corps	23,385	1,170	1,073	5 %	19,687	718	662	3 %
New York City	50,134	3,980	3,725	7 %	50,433	3,629	3,400	7 %
Indianapolis Mon'tal	3,521	518	483	14 %	3,725	594	552	15 %
Richmond	4,842	441	418	9 %	5,095	520	487	10 %
Philadelphia	10,914	1,341	1,252	11 %	10,333	1,337	1,235	12 %
California International	6,238	1,292	1,195	19 %	5,793	1,291	1,185	20 %
Houston	6,945	698	651	9 %	7,133	698	648	9 %
Boston	31,210	10,564	10,046	32 %	26,635	12,792	12,218	46 %
Bayshore	2,017	314	300	15 %	2,008	341	329	16 %
Ottawa	5,324	812	745	14 %	4,501	806	750	17 %
Mountains 2 Beach	1,617	399	370	23 %	1,586	452	419	26 %
TOTAL	257,623	35,887	33,755	13 %	243,242	36,863	34,737	14 %
Notes: 1. BQ = Number of Runners who met the minimum Boston Qualifying Standard 2. BQ2015 = Number of Runners who met the Cutoff for the 2015 Boston Marathon (BQ minus 1m 2s) 3. BQ2015% = Percentage of finishers meeting the BQ 20015 cutoff time. 4. AG = Age Group on the day of the feeder race, not the subsequent year's Boston Marathon.    This is a small source of error, as a person may "age-up" for the subsequent year's Boston Marathon.

Analysis
Looking at the table above: 257,623 runners finished a 2015 qualifying race, whereas 243,242 finished a 2016 race: 14,000 fewer people. However, more people met the minimum BQ standard 35,499 for the 2016 qualifying year versus 34,729 for the 2015 qualifying year. Moreover, more people met the 1 minute and 2 second cutoff in the 2016 qualifying year so far than did in 2015.

If the Boston Marathon registration opened today - assuming the same proportion of qualified runners apply for the race (see objective and methodology) - there wouldn't be enough spots for everyone. We have to increase the cutoff so that we whittle the 34,737 people (who met the 2015 cutoff in a 2016 qualifying race) down to 33,755 the number of people who met the Cutoff for 2015.

Through a numerical modelling approach, the answer to the solution, of what the cutoff should be becomes 90 seconds.

At 90 seconds, 33,765 people will make it into the marathon. (10 more than this year).

At 91 seconds, 33,731 people will make it into the marathon. (24 fewer than this year)

Table 2: Projected qualifiers by AG based on an 90 second cutoff.

AG	Finishers	BQ	BQ2015 @62s	BQ2016 @90s	BQ2016%
F18-34	41,240	5,136	4,840	4,711	11 %
F35-39	16,721	2,440	2,306	2,248	13 %
F40-44	16,225	2,476	2,302	2,230	14 %
F45-49	12,094	2,539	2,383	2,308	19 %
F50-54	7,942	1,572	1,486	1,443	18 %
F55-59	3,978	844	798	787	20 %
F60-64	1,621	383	366	362	22 %
F65-69	513	111	109	107	21 %
F70-74	155	32	30	30	19 %
F75-79	28	4	4	4	14 %
F80+	6	3	3	3	50 %
M18-34	39,831	4,892	4,651	4,533	11 %
M35-39	21,881	2,658	2,491	2,423	11 %
M40-44	24,574	3,195	2,996	2,901	12 %
M45-49	21,375	3,879	3,647	3,540	17 %
M50-54	16,786	2,965	2,769	2,675	16 %
M55-59	9,913	1,892	1,789	1,737	18 %
M60-64	5,183	1,113	1,065	1,034	20 %
M65-69	2,163	520	500	492	23 %
M70-74	765	166	160	156	20 %
M75-79	206	35	34	33	16 %
M80+	42	8	8	8	19 %
Total	243,242	36,863	34,737	33,765	14 %
Notes: 1. BQ = Number of Runners who met the minimum Boston Qualifying Standard 2. BQ2015 = Number of Runners who met the Cutoff for the 2015 Boston Marathon (BQ minus 1m 2s) 3. BQ2016 = Number of Runners who met the projected Cutoff for the 2016 Boston Marathon (BQ minus 90s) 4. BQ2016% = Percentage of finishers meeting the projected BQ 20016 cutoff time. 4. AG = Age Group on the day of the feeder race, not the subsequent year's Boston Marathon.    This is a small source of error, as a person may "age-up" for the subsequent year's Boston Marathon.

Other Interesting Numbers:

Combined, to date - Year vs Year Analysis, By Age Group

	2015 Qualifying Year				2016 Qualifying Year
AG	Finishers	BQ	BQ2015	BQ2015%	Finishers	BQ	BQ2015	BQ2015%
F18-34	42,777	4,530	4,273	10 %	41,240	5,136	4,840	12 %
F35-39	17,221	2,321	2,171	13 %	16,721	2,440	2,306	14 %
F40-44	16,830	2,423	2,284	14 %	16,225	2,476	2,302	14 %
F45-49	12,617	2,518	2,400	19 %	12,094	2,539	2,383	20 %
F50-54	8,469	1,639	1,547	18 %	7,942	1,572	1,486	19 %
F55-59	3,904	746	712	18 %	3,978	844	798	20 %
F60-64	1,670	339	323	19 %	1,621	383	366	23 %
F65-69	510	115	107	21 %	513	111	109	21 %
F70-74	134	23	23	17 %	155	32	30	19 %
F75-79	19	5	5	26 %	28	4	4	14 %
F80+	7	2	1	14 %	6	3	3	50 %
M18-34	43,631	4,784	4,517	10 %	39,831	4,892	4,651	12 %
M35-39	23,616	2,709	2,504	11 %	21,881	2,658	2,491	11 %
M40-44	26,716	3,363	3,143	12 %	24,574	3,195	2,996	12 %
M45-49	22,773	3,779	3,547	16 %	21,375	3,879	3,647	17 %
M50-54	17,882	2,947	2,730	15 %	16,786	2,965	2,769	16 %
M55-59	10,139	1,824	1,726	17 %	9,913	1,892	1,789	18 %
M60-64	5,495	1,105	1,052	19 %	5,183	1,113	1,065	21 %
M65-69	2,188	496	480	22 %	2,163	520	500	23 %
M70-74	779	176	168	22 %	765	166	160	21 %
M75-79	192	37	36	19 %	206	35	34	17 %
M80+	54	6	6	11 %	42	8	8	19 %
Total	257,623	35,887	33,755	13 %	243,242	36,863	34,737	14 %
Notes: 1. BQ = Number of Runners who met the minimum Boston Qualifying Standard 2. BQ2015 = Number of Runners who met the Cutoff for the 2015 Boston Marathon (BQ minus 1m 2s) 3. BQ2015% = Percentage of finishers meeting the BQ 20015 cutoff time. 4. AG = Age Group on the day of the feeder race, not the subsequent year's Boston Marathon.    This is a small source of error, as a person may "age-up" for the subsequent year's Boston Marathon.