Analysis of proportional data in reproductive and developmental toxicity studies: comparison of logit transformation, arcsine square root transformation, and nonparametric analysis
We conducted power calculations to compare different approaches (nonparametric, arcsine square root-transformed, logit-transformed, untransformed) for analyzing litter-based proportional data. A reproductive toxicity study with a control and one treated group provided data for two endpoints: prenatal loss, and fertility by in utero insemination (IUI). Type I error and power were estimated by 10,000 simulations based on two-sample one-tailed t-tests with varying numbers of litters per group. To further compare the different approaches, we conducted additional analyses with the mean proportions shifted toward zero to produce illustrative scenarios. Analyses based on logit-transformed proportions had greater power than those based on untransformed or arcsine square root-transformed proportions, or nonparametric procedures.
Complete Metadata
| accessLevel | public |
|---|---|
| bureauCode |
[
"020:00"
]
|
| contactPoint |
{
"fn": "Michael Narotsky",
"hasEmail": "mailto:narotsky.michael@epa.gov"
}
|
| description | We conducted power calculations to compare different approaches (nonparametric, arcsine square root-transformed, logit-transformed, untransformed) for analyzing litter-based proportional data. A reproductive toxicity study with a control and one treated group provided data for two endpoints: prenatal loss, and fertility by in utero insemination (IUI). Type I error and power were estimated by 10,000 simulations based on two-sample one-tailed t-tests with varying numbers of litters per group. To further compare the different approaches, we conducted additional analyses with the mean proportions shifted toward zero to produce illustrative scenarios. Analyses based on logit-transformed proportions had greater power than those based on untransformed or arcsine square root-transformed proportions, or nonparametric procedures. |
| distribution |
[
{
"title": "PowerManuscriptTableFigureData.xlsx",
"mediaType": "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
"downloadURL": "https://pasteur.epa.gov/uploads/10.23719/1503388/PowerManuscriptTableFigureData.xlsx"
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|
| identifier | https://doi.org/10.23719/1503388 |
| keyword |
[
"Developmental Toxicity",
"arcsine square root transformation",
"logit transformation",
"proportional data",
"statistical power"
]
|
| license | https://pasteur.epa.gov/license/sciencehub-license.html |
| modified | 2019-04-15 |
| programCode |
[
"020:000"
]
|
| publisher |
{
"name": "U.S. EPA Office of Research and Development (ORD)",
"subOrganizationOf": {
"name": "U.S. Environmental Protection Agency",
"subOrganizationOf": {
"name": "U.S. Government"
}
}
}
|
| references |
null
|
| rights |
null
|
| title | Analysis of proportional data in reproductive and developmental toxicity studies: comparison of logit transformation, arcsine square root transformation, and nonparametric analysis |
