Somewhat. April 30 is in the less common part of the calendar in these historical U.S. records. It ranks #322 of 366 dates by total births from 1994 through 2014. Rank #1 means most common.
April 30 had 226,221 births across 21 occurrences, or 10,772 births per occurrence. That is 0.264% of the 85,712,738-birth sample, or about 1 in 379 recorded births.
It ranks #24 of the 30 April dates.
Does April 30 stay below nearby same-weekday dates?
Yes, by a small margin. In SSA 2000–2014, the primary comparison gives -1.9%. That means April 30 had 1.9% fewer births than same-weekday dates 7 and 14 days away. It was below its controls in all 15 years.
Every planned alternative comparison has the same direction. With only the 7-day controls, the result is -1.3%. With only the 14-day controls, it is -2.4%. Without holiday exclusions, it is -1.9%.
The difference is small. It describes these records only. It does not show why births differed.
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 April 30 with controls from the same year.
| Comparison | Years | Control observations | Difference |
|---|---|---|---|
| 7 and 14 days, holidays excluded (primary) | 15 | 60 | -1.9% |
| 7 days only | 15 | 30 | -1.3% |
| 14 days only | 15 | 30 | -2.4% |
| 7 and 14 days, no holiday exclusions | 15 | 60 | -1.9% |
How were the comparison dates chosen?
The primary controls are April 16, April 23, May 7, and May 14 in the same year. Each is 7 or 14 days from April 30, so it falls on the same weekday.
None of these controls fell on an excluded holiday. We exclude holidays under the standard observed federal holiday rules. We also exclude Christmas Eve, December 26, and the Friday after Thanksgiving.
By five-year period, the primary differences are -1.4% for 2000–2004, -1.8% for 2005–2009, and -2.3% 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 April 30 rank change over time?
Yes. We ranked 365 recurring dates by SSA births in each five-year period. April 30 placed #217 in 2000–2004, #347 in 2005–2009, and #223 in 2010–2014. The three ranks span 130 places.
The median span for all 365 recurring dates is 159 places. This span is below that median.
Each period has only five occurrences of April 30. 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 April guide for the full month ranking. See also the April 1 study.
The methodology explains ranks and shares. Use the birthday checker to compare another date.