Appendix.

Number and Percent of Studies Excluded from the Meta-Analyses by Exclusion Code

Reason for exclusion from meta-analyses	Number of studies excluded	Percent
Spanking not linked with child outcomes (e.g., prevalence only).	238	16
Not an empirical article (e.g., a literature review).	221	15
Definition of physical punishment included harsh methods of physical punishment beyond spanking, slapping, or hitting.	194	13
Spanking was not measured in the study.	171	11
Study was an unpublished dissertation.	104	7
Article was not relevant.	85	6
Attitudes toward, and not use of, physical punishment was assessed.	82	5
Study was of physical punishment in schools or other institutions.	73	5
Study did not include a bivariate association between spanking and the child outcome.	61	4
Study was of an intervention to reduce physical punishment.	47	3
Available statistics were unclear, insufficient, or inappropriate for the meta-analyses.	46	3
Spanking was combined with yelling or some form of psychological aggression.	44	3
Study was not available in English.	32	2
Spanking was combined with other types of discipline.	30	2
Study was published as a book chapter or conference presentation.	23	2
Study used same dataset as another study in the meta-analysis.	23	2
Dependent variable did not fit into other outcome categories.	11	1
Spanking was of animals, not children.	5	<1
Article was unavailable through interlibrary loan.	3	<1
Spanking measure included threats of spanking.	3	<1
Physical punishment measure was nontraditional (i.e., aversive noise; washing mouth out with soap).	2	<1
Study involved a special population of children (chromosomal abnormality).	1	<1
Total number of excluded studies	1,499	100%