replicate.prop2 {vcmeta}

Compares and combines 2-group proportion differences in original and follow-up studies

Description

This function computes confidence intervals from an original study and a follow-up study where the effect size is a 2-group proportion difference. Confidence intervals for the difference and average effect size are also computed. The confidence level for the difference is 1 – 2*alpha, which is recommended for equivalence testing.

Usage

replicate.prop2(alpha, f11, f12, n11, n12, f21, f22, n21, n22)

Arguments

alpha

alpha level for 1-alpha confidence

f11

frequency count for group 1 in original study

f12

frequency count for group 2 in original study

n11

sample size for group 1 in original study

n12

sample size for group 2 in original study

f21

frequency count for group 1 in follow-up study

f22

frequency count for group 2 in follow-up study

n21

sample size for group 1 in follow-up study

n22

sample size for group 2 in follow-up study

Value

A 4-row matrix. The rows are:

• Row 1 summarizes the original study

• Row 2 summarizes the follow-up study

• Row 3 estimates the difference in proportion differences

• Row 4 estimates the average proportion difference

The columns are:

• Estimate - proportion difference estimate (single study, difference, average)

• SE - standard error

• z - z-value

• p - p-value

• LL - lower limit of the confidence interval

• UL - upper limit of the confidence interval

References

Bonett DG (2021). “Design and analysis of replication studies.” Organizational Research Methods, 24(3), 513–529. ISSN 1094-4281, doi:10.1177/1094428120911088.

Examples

replicate.prop2(.05, 21, 16, 40, 40, 19, 13, 60, 60)

# Should return:
#                         Estimate         SE         z         p
# Original:             0.11904762 0.10805233 1.1017590 0.2705665
# Follow-up:            0.09677419 0.07965047 1.2149858 0.2243715
# Original - Follow-up: 0.02359056 0.13542107 0.1742016 0.8617070
# Average:              0.11015594 0.06771053 1.6268656 0.1037656
#                                LL        UL
# Original:             -0.09273105 0.3308263
# Follow-up:            -0.05933787 0.2528863
# Original - Follow-up: -0.19915727 0.2463384
# Average:              -0.02255427 0.2428661