Table 1.

Inclusionary criteria for article selection and coding

1. The study must use a genetically-sensitive (i.e., twin or family) research design.

2. The study must either directly report the genetic and/or environmental correlation between reading and ADHD symptoms and/or reading and math, or:    a. Provide path estimates that can be converted into correlations with the formula: $r_g=\frac{a_{21}{a}_{11}}{\sqrt{a_{11}^2*\left(a_{21+}^2{a}_{22}^2\right)}}$, or    b. Report DeFries-Fulker estimates that can be converted with the formula: $r_g=\sqrt{\frac{B_{2\left(xy\right)}{B}_{2\left(yx\right)}}{B_{2\left(x\right)}{B}_{2\left(y\right)}}}$

3. When a study uses a model comparison approach and reports the results of several models that may be relevant to the present study, only the chosen final model will be coded.

4. The assessment used for reading, ADHD symptoms, or math will be coded as a reading, ADHD symptom, or math composite when many different assessments were used, but not when multiple subtests from the same assessment were included.