Grandma's keeps Boston Cutoff at 90 seconds

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 23 of the top 25 feeder marathons complete, the current trend for the 2016 Boston Marathon Cutoff is 90 seconds. Grandma's marathon, with over 6000 participants is a big enough marathon to impact the Boston Marathon projected cutoff. This year's edition had similar results as last year. There were 100 fewer finishers, but 19 more people who beat the 1m2s cutoff from the 2015 Boston Marathon. Since the results were similar to last year, this kept the projected cutoff at 90 seconds.

Only 2 more left (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 the 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 %
Grandma's	6,173	1,108	1,047	17 %	6,075	1,134	1,066	18 %
TOTAL	263,796	36,995	34,802	13 %	249,317	37,997	35,803	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: 263,796 runners finished a 2015 "feeder" qualifying race, whereas 249,317 finished a 2016 "feeder" race: 14,479 fewer people. However, more people met the minimum BQ standard 37,997 for the 2016 qualifying year versus 36,995 for the 2015 qualifying year. Moreover, 1001 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 35,803 people (who met the 2015 cutoff in a 2016 qualifying race) down to 34,802 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, 34,799 people will make it into the marathon. (only 3 fewer than this year).

Table 2: Projected qualifiers, from this years races, by AG based on an 90 second cutoff.

AG	Finishers	BQ	BQ minus 62s	BQ minus 90s	BQ2016%
F18-34	42,545	5,355	5,041	4,908	12 %
F35-39	17,133	2,518	2,380	2,321	14 %
F40-44	16,547	2,543	2,366	2,293	14 %
F45-49	12,324	2,585	2,426	2,351	19 %
F50-54	8,148	1,624	1,537	1,493	18 %
F55-59	4,075	874	824	813	20 %
F60-64	1,667	393	376	372	22 %
F65-69	529	112	110	108	20 %
F70-74	158	32	30	30	19 %
F75-79	30	5	5	5	17 %
F80+	6	3	3	3	50 %
M18-34	41,185	5,148	4,895	4,765	12 %
M35-39	22,367	2,726	2,552	2,483	11 %
M40-44	24,992	3,264	3,061	2,964	12 %
M45-49	21,734	3,953	3,717	3,607	17 %
M50-54	17,134	3,029	2,828	2,733	16 %
M55-59	10,146	1,932	1,828	1,770	17 %
M60-64	5,336	1,148	1,099	1,068	20 %
M65-69	2,227	537	516	508	23 %
M70-74	780	172	166	162	21 %
M75-79	210	35	34	33	16 %
M80+	44	9	9	9	20 %
Total	249,317	37,997	35,803	34,799	14 %
Notes: 1. BQ = Number of Runners who met the minimum Boston Qualifying Standard 2. BQ minus 62s = Number of Runners from this year's races who would have met the Cutoff for the 2015 Boston Marathon (BQ minus 1m 2s) 3. BQ minus 90s = Number of Runners from this year's races who would meet 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.