No. October 15 has more recorded births than most dates in these historical U.S. records. It ranks #131 of 366 dates by total births from 1994 through 2014. Rank #1 means most common.
October 15 had 237,459 births across 21 occurrences, or 11,308 births per occurrence. That is 0.277% of the 85,712,738-birth sample, or about 1 in 361 recorded births.
Within October, October 15 ranks #13 of 31 dates.
Does October 15 differ from nearby same-weekday dates?
Not clearly. In SSA 2000–2014, the primary comparison gives -0.5%. The three comparisons with holiday exclusions all stay within 1% of the controls.
When weekdays match, October 15 looks much like the dates around it.
In the primary comparison, October 15 was above its controls in six years and below them in nine.
Baseline ranks use historical U.S. CDC/NCHS and SSA records, 1994–2014. The percentage differences use SSA 2000–2014 alone. Each table row compares October 15 with controls from the same year.
| Comparison | Years | Control observations | Difference |
|---|---|---|---|
| 7 and 14 days, holidays excluded (primary) | 15 | 57 | -0.5% |
| 7 days only | 15 | 27 | -0.1% |
| 14 days only | 15 | 30 | -0.9% |
| 7 and 14 days, no holiday exclusions | 15 | 60 | -0.4% |
How were the comparison dates chosen?
The primary controls are October 1, October 8, October 22, and October 29 in the same year. Each is 7 or 14 days from October 15, so it falls on the same weekday.
In some years, a planned control falls on Columbus Day. We remove that control under the standard observed federal holiday rules. The year keeps its other controls.
By five-year period, the primary differences are -1.2% for 2000–2004, -0.2% for 2005–2009, and -0.1% for 2010–2014.
To combine the years, we divide the summed target births by the summed annual control means. Then we subtract one and multiply by 100. The result is not an average of annual percentages.
Does the October 15 rank change over time?
Yes, more than most dates. We ranked 365 recurring dates by SSA births in each five-year period. October 15 placed #94 in 2000–2004, #277 in 2005–2009, and #71 in 2010–2014. The three ranks span 206 places.
The median span for all 365 recurring dates is 159 places. This span is well above that median.
Each period has only five occurrences of October 15. It fell on a weekend twice in 2005–2009 and once in each other period. The period with more weekend occurrences has the less common rank.
These ranks use raw birth counts. The ranking-stability study also compares annual shares and weekday-relative scores for every date.
Sources and limits
Baseline totals and ranks use FiveThirtyEight’s pinned U.S. birth files. We use CDC/NCHS for 1994–1999 and SSA for 2000–2014, so no year comes from both sources. Annual comparisons use SSA alone.
The source series have different administrative coverage. These records do not describe worldwide births, everyone alive today, or current birth rates.
The daily totals do not record delivery methods or scheduling decisions. Weekday matching does not remove every seasonal difference. Federal holiday rules identify calendar dates, not hospital schedules.
Use the October guide for the full month ranking. Compare the nearby October 13 study. See also the October 31 study.
The methodology explains ranks and shares. Use the birthday checker to compare another date.