Key points are not available for this paper at this time.
Susan Ring Andrews, Janet Berstein Blumenthal, Dale L. Johnson, Alfred J. Kahn, Carol J. Ferguson, Thomas M. Lasater, Paul E. Malone, Doris B. Wallace, The Skills of Mothering: A Study of Parent Child Development Centers, Monographs of the Society for Research in Child Development, Vol. 47, No. 6, The Skills of Mothering: A Study of Parent Child Development Centers (1982), pp. 1-83
Andrews et al. (Fri,) studied this question.