What is the advantage of using affine gap scores?

Larsen and Buss present four key research designs used in the behavioral genetic study of personality. Briefly review the key features of these designs and discuss the advantages and disadvantages of each design. Why would it be particularly powerful for a set of results (such as heritability and environmental estimates) to be documented using more than one design? Refer to a specific personality trait in formulating your answer to this question

ADHD is a highly heritable trait with published broad sense heritability estimates in the range of 0.6- 0.9. Larsson et al. 2014 (doi: 10.1017/S0033291713002493 ) reported the concordance values shown in the table below for pairs of monozygotic (MZ) or dizygotic (DZ) twins with data for male and female pairs shown separately, using data from the Swedish twin register (59,000 twin pairs, born between 1959 and 2001). Male MZ twins Male DZ twins Female MZ twins Female DZ twins 56% 16% 37% 13% Based on the data in this table, does ADHD appear to be more heritable in males or females? Provide one sentence of rationale to support your answer.

Consider a study designed to estimate the role that certain characteristics play on predicting persons who are at greatest risk of developing arthritis in one or more joints. The authors have noted a lost-to-followup rate of 26%. Why is this cause for concern?   It is cause for concern because those who remain in the study may be at a systematically higher risk than those not followed   It is not cause for concern in this type of study; the concern exists only for randomized trials   It is cause for concern because those who remain in the study may be at a systematically higher or lower risk than those not followed   It is cause for concern because those who remain in the study may be at a systematically lower risk than those not followed