Predicting with Genetic Data, Part 1 – the Method


An article entitled “Your Success is Shaped by Your Genes” from the January – February Harvard Business Review caught my eye. I guess that was the goal of the catchy and controversial title, which implies that your DNA is your destiny in terms of how successful you will be in formal education and thus in life. The goal of the researchers was to see if existing genetic data could be used to predict if carrying a certain gene could predict which developmental benchmarks children would reach and when they would reach them.

The Belsky et al. study, published in the June 2016 issue of Psychological Science, claims that polygenic scores are a way to measure the success of people throughout their lives. It is based on a 2013 genome-wide association study by Haller et al., which hinted there may be a link between genetic predictors and educational attainment using 100,000 individuals. The 2013 study said that some people carry alternative forms of genes found on a chromosome, or alleles, described used a polygenic score. The higher the score, the increased potential for doing well in school. Traditionally, the association of how frequent people have genetic markers and traits is studied using linear regression least squares approach.

Belsky and his colleagues used 918 people over a four-decade period in Dunedin, New Zealand. The study members were 52% male born between April 1972 and March 1973, representing a full range of socioeconomic status among the general population of that city. The cohort had less than 7% self-identified as having non-European ancestry, which matches the racial makeup of that city. Educational attainment was tracked throughout the cohort’s life and was defined as the highest formal degree completed by the time the cohorts were 38 years old.

The data did have a slight correlation – study participants with higher polygenic scores were slightly more ‘successful’ than those with lower scores. It’s important to note that the study authors defined success as how much education was attained and how much money was earned as a result of that in a career. Additionally a key finding from this study that is CRUCIAL that the general public may miss in the HBR article – the EFFECT of the score was VERY SMALL – just 1 – 4% of the variance. The researchers concluded that some people with low scores had successful lives and some with high scores did not have successful lives. So this genetic data is one way to explore that there MAY be a connection between genetics and educational success but it is by no means conclusive.

Next week I want to move beyond the methods of the study and look at the ethical implications of this study.

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