TY  - BOOK
AU  - Nagel,Ilene H.
TI  - Validity issues in evaluative research
T2  - Sage contemporary social science issues ; 23
SN  - 0803905815
AV  - H62 .V27 1976
U1  - 001.4 19
PY  - 1976///, c1975
CY  - Beverly Hills, Calif.
PB  - Sage Publications
KW  - Evaluation research (Social action programs)
N1  - "Originally appeared as a special issue of Sociological methods & research (volume 4, number 1, August 1975)."; Includes bibliographies
ER  -