Distribution of NCS Mothers’ Characteristics Compared With Population1 Distribution by Recruitment Strategy

Mother’s Characteristics at DeliveryRecruitment Strategy
NCS, %Population, %aNCS, %Population, %NCS, %Population, %NCS, %Population, %NCS, %Population, %
Race and/or ethnicity
 Non-Hispanic white615857507652*57503555
 Non-Hispanic black581114112222221417
 Non-Hispanic other20126116866105
Age, y
 Less than high school1716161761422182018
 High school212122291023**21292927
 Some college34253228252629262525
 College or higher27373027603728272730
Marital status
 Not married21313941183848465542
  • Population distribution is computed as simple average of percentage distributions across the PSUs in each recruitment strategy. NCS distribution is computed by using PROC SURVEYFREQ in SAS. The hypothesis that the NCS percentage equals the population percentage was tested by using a 1-way table χ2 test statistic with the Rao-Scott correction for a clustered sample design. This test was conducted by characteristic and method.

  • a Population data are based on 2010 natality data for mothers 18 y of age and over computed for the NCS PSUs.

  • * P < .05,

  • ** P < .001.