describe_studies {metamedian}

Descriptive statistics for meta-analyzing studies reporting medians

Description

This function performs some descriptive analyses. Specifically, this function describes: (i) the number of studies reporting various summary statistics, (ii) the Bowley skewness (Bowley, 1901) in the primary studies, and (iii) the results of a skewness test (Shi et al., 2023) applied to the summary statistics reported in the primary studies.

Usage

describe_studies(data, method = "qe", group_labels = c("Group 1", "Group 2"))

Arguments

data

data frame containing the study-specific summary data. For one-group studies, this data frame can contain the following columns:

min.g1	minimum value.
q1.g1	first quartile.
med.g1	median.
q3.g1	third quartile.
max.g1	maximum value.
n.g1	sample size.
mean.g1	sample mean.
sd.g1	sample standard deviation.
med.var.g1	sampling variance of the median (only applicable when median_method="cd").
med.ci.lb.g1	lower confidence interval bound around the median (only applicable when median_method="cd").
med.ci.ub.g1	upper confidence interval bound around the median (only applicable when median_method="cd").
alpha.1.g1	\alpha_1 values from Ozturk and Balakrishnan (2020) (only applicable when median_method="cd").
alpha.2.g1	\alpha_2 values from Ozturk and Balakrishnan (2020) (only applicable when median_method="cd").

For two group studies, this data frame can also contain the following columns for the summary data of the second group: min.g2, q1.g2, med.g2, q3.g2, max.g2, n.g2, mean.g2, and sd.g2.

method

character string specifying the sets of summary statistics to consider. If this argument is set to "cd", the summary statistics for the CD method (see C1/C2, C3, C4, C5 in cd) are considered. Otherwise, the S1, S2, S3, and S4 summary statistics described in qe are considered.

group_labels

vector of character strings specifying the names corresponding to groups 1 and 2, respectively. This argument is only applicable when the meta-analysis consists of two-group studies. By default, this argument is set to c('Group 1', 'Group 2').

Value

an object of class "describe_studies". The object is a list with the following components:

description

data frame containing the results of the descriptive analyses.

bowley_g1

vector containing the study-specific Bowley skewness values in group 1.

bowley_g2

vector containing the study-specific Bowley skewness values in group 2.

skew_test_g1

data frame containing the results of the skewness test of Shi et al. (2023) based on the group 1 data. The data frame contains the test statistic values, critical values at the 0.05 level, and indicators of statistical significance at the 0.05 level.

skew_test_g2

data frame containing the results of the skewness test of Shi et al. (2023) based on the group 2 data. The data frame contains the test statistic values, critical values at the 0.05 level, and indicators of statistical significance at the 0.05 level.

The results are printed with the print.describe_studies function.

References

Bowley, A.L. (1901). Elements of Statistics. London: P.S. King & Son.

McGrath S., Zhao X., Ozturk O., Katzenschlager S., Steele R., and Benedetti A. (in press). metamedian: An R package for meta-analyzing studies reporting medians. Research Synthesis Methods.

Shi J., Luo D., Wan X., Yue L., Liu J., Bian Z., Tong T. (2023). Detecting the skewness of data from the five-number summary and its application in meta-analysis. Statistical Methods in Medical Research. 0(0).

Examples

describe_studies(data = dat.age, group_labels = c("Nonsurvivors", "Survivors"))