I think much of the high apparent strong correlation between academics and ECs when looking to % 2’s ratings in different AI deciles relates to % 2 or better being an average over a huge sample, rather than individual applicants. If you you look at averages over a large sample rather than individuals, correlations with scores (2/3 of AI is based on test scores) often seem remarkably strong. For example, it’s not unusual to have a R^2 of 0.8 to 0.9 between average graduation rate of a college and average SAT score of a college, among a large list of colleges. One might think this means test scores can explain the vast majority of variance in a particular student’s chance of graduating. However, when one tries to instead predict chance of graduation for individual students with their scores rather than the average graduation rate for the full college, the results are completely different. R^2 often drops to <0.1, with some other factors typically being stronger predictors than scores, such as HS GPA.
The specific numbers mentioned in the Arcidiacono Harvard applicant analysis are quoted below for unhooked White applicants in the baseline sample. All ratings appear to have notable correlations with AI decile, yet AI alone only explained a small portion of variance in admissions decisions.
Portion of White Unhooked Applicants Receiving a Good 2 or Better Rating
Top AI Declie – 97% academic, 33% EC, 48% LOR, 30% personal, 63% interview
2nd AI Declie – 93% academic, 30% EC, 43% LOR, 28% personal, 57% interview
3rd AI Declie – 82% academic, 27% EC, 38% LOR, 26% personal, 49% interview
4th AI Declie – 68% academic, 27% EC, 33% LOR, 23% personal, 43% interview
5th AI Declie – 50% academic, 25% EC, 30% LOR, 23% personal, 38% interview
6th AI Declie – 26% academic, 24% EC, 25% LOR, 20% personal, 33% interview
7th AI Declie – 9% academic, 22% EC, 22% LOR, 19% personal, 26% interview
8th AI Declie – 2% academic, 20% EC, 17% LOR, 16% personal, 19% interview
9th AI Declie – 0.4% academic, 16% EC, 12% LOR, 13% personal, 13% interview
Last AI Declie – 0.1% academic, 11% EC, 7% LOR, 8% personal, 7% interview
I agree with many of the reasons you listed for the correlation. The academic type ECs have a more obvious reasons for the correlation. However, as summarized below, the most common “primary ECs” (EC listed first or 2nd on application) were athletics and community service. It seems less obvious that a high AI decile would have a strong correlation with athletics and community service success. There may be some secondary influences, such as the kids with higher AI deciles are more likely to be encouraged to pursue extreme community service activities and have opportunity to do so. Kids in a high AI decile are also more likely to have financial support from their parents, which is relevant for both athletic and community service success. There are also personality traits that are relevant to both athletic and academic success, such as dedication and tenacity.
Most Common “Primary” ECs Among White Applicants
- Athletics – 45% (varsity + JV + club)
- Community Service – 22%
- “Other” – 14%
- Music – 12%
- Academic – 11%
6… Politics – 10%
- Work – 9%
- Science & Math – 8%
- Debate – 7%
- Drama – 6%