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 same results can be obtained using the meta.lc.prop2 function with appropriate contrast coefficients. 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