The Social Network Index (Cohen et al. 1997) assessed the extent of involvement in 10 types of social relationships separately (e.g. relatives, co-workers, neighbors) by querying the total number of persons seen or talked to every two weeks in person or via the internet or phone at Wave 2. A summed score across all relationships exhibits relatively low internal consistency (α=0.62) yet good test-retest reliability (ICC=0.70) (Hatzenbuehler et al. 2011; Ruan et al. 2008). In the NESARC data, the scale of each individual item was truncated to 50 persons yielding a final summed index with a range of 0 to 235. We truncated the individual scores to 7 persons, which provided a more normal distribution in the summed index (range 0 to 51).
