es_from_plot_means {metaConvert}

Converts the means and bounds of an error bar (generally extracted from a plot) into four effect measures (SMD, MD, OR, COR)

Description

Converts the means and bounds of an error bar (generally extracted from a plot) into four effect measures (SMD, MD, OR, COR)

Usage

es_from_plot_means(
  n_exp,
  n_nexp,
  plot_mean_exp,
  plot_mean_nexp,
  plot_mean_sd_lo_exp,
  plot_mean_sd_lo_nexp,
  plot_mean_sd_up_exp,
  plot_mean_sd_up_nexp,
  plot_mean_se_lo_exp,
  plot_mean_se_lo_nexp,
  plot_mean_se_up_exp,
  plot_mean_se_up_nexp,
  plot_mean_ci_lo_exp,
  plot_mean_ci_lo_nexp,
  plot_mean_ci_up_exp,
  plot_mean_ci_up_nexp,
  smd_to_cor = "viechtbauer",
  reverse_plot_means
)

Arguments

n_exp

number of participants in the experimental/exposed group.

n_nexp

number of participants in the non-experimental/non-exposed group.

plot_mean_exp

mean of participants in the experimental/exposed group (extracted from a plot).

plot_mean_nexp

mean of participants in the non-experimental/non-exposed group (extracted from a plot).

plot_mean_sd_lo_exp

lower bound of an error bar depicting -1 SD from the mean of the experimental/exposed group (extracted from a plot).

plot_mean_sd_lo_nexp

lower bound of an error bar depicting -1 SD from the mean of the non-experimental/non-exposed group (extracted from a plot).

plot_mean_sd_up_exp

upper bound of an error bar depicting +1 SD from the mean of the experimental/exposed group (extracted from a plot).

plot_mean_sd_up_nexp

upper bound of an error bar depicting +1 SD from the mean of the non-experimental/non-exposed group (extracted from a plot).

plot_mean_se_lo_exp

lower bound of an error bar depicting -1 SE from the mean of the experimental/exposed group (extracted from a plot).

plot_mean_se_lo_nexp

lower bound of an error bar depicting -1 SE from the mean of the non-experimental/non-exposed group (extracted from a plot).

plot_mean_se_up_exp

upper bound of an error bar depicting +1 SE from the mean of the experimental/exposed group (extracted from a plot).

plot_mean_se_up_nexp

upper bound of an error bar depicting +1 SE from the mean of the non-experimental/non-exposed group (extracted from a plot).

plot_mean_ci_lo_exp

lower bound of an error bar depicting the 95% CI of the mean of the experimental/exposed group (extracted from a plot).

plot_mean_ci_lo_nexp

lower bound of an error bar depicting the 95% CI of the mean of the non-experimental/non-exposed group (extracted from a plot).

plot_mean_ci_up_exp

upper bound of an error bar depicting the 95% CI of the mean of the experimental/exposed group (extracted from a plot).

plot_mean_ci_up_nexp

upper bound of an error bar depicting the 95% CI of the mean of the non-experimental/non-exposed group (extracted from a plot).

smd_to_cor

formula used to convert the cohen_d value into a coefficient correlation (see details).

reverse_plot_means

a logical value indicating whether the direction of the generated effect sizes should be flipped.

Details

This function uses the bounds of an error bar of a mean obtained from a plot into a standard deviation. Then, a mean difference (MD), Cohen's d (D), and Hedges' g (G) are estimated. Odds ratio (OR), risk ratio (RR) and correlation coefficients (R/Z) are converted from the Cohen's d value.

To convert the bound of an error bar into a standard deviation, this function always prioritizes information from the plot_mean_sd_* arguments, then those from the plot_mean_se_* arguments, then those from the plot_mean_ci_* arguments.

1. If the bounds of the standard deviations are provided, the following formulas are used:

   mean\_sd\_lo\_exp = plot\_mean\_exp - plot\_mean\_sd\_lo\_exp

   mean\_sd\_up\_exp = plot\_mean\_sd\_up\_exp - plot\_mean\_exp

   mean\_sd\_exp = \frac{mean\_sd\_lo\_exp + mean\_sd\_up\_exp}{2}

mean\_sd\_lo\_nexp = plot\_mean\_nexp - plot\_mean\_sd\_lo\_nexp

mean\_sd\_up\_nexp = plot\_mean\_sd\_up\_nexp - plot\_mean\_nexp

mean\_sd\_nexp = \frac{mean\_sd\_lo\_nexp + mean\_sd\_up\_nexp}{2}

Note that if only one bound (e.g., the upper bound) is provided, it will be the only information used to estimate the standard deviation value.

Then, calculations of the es_from_means_sd are used.

1. If the bounds of the standard errors are provided, the following formulas are used:

   mean\_se\_lo\_exp = plot\_mean\_exp - plot\_mean\_se\_lo\_exp

   mean\_se\_up\_exp = plot\_mean\_se\_up\_exp - plot\_mean\_exp

   mean\_se\_exp = \frac{mean\_se\_lo\_exp + mean\_se\_up\_exp}{2}

mean\_se\_lo\_nexp = plot\_mean\_nexp - plot\_mean\_se\_lo\_nexp

mean\_se\_up\_nexp = plot\_mean\_se\_up\_nexp - plot\_mean\_nexp

mean\_se\_nexp = \frac{mean\_se\_lo\_nexp + mean\_se\_up\_nexp}{2}

Note that if only one bound (e.g., the upper bound) is provided, it will be the only information used to estimate the standard error value.

Then, calculations of the es_from_means_se() are used.

1. If the bounds of the 95% confidence intervals are provided, the calculations of the es_from_means_ci are used.

Value

This function estimates and converts between several effect size measures.

natural effect size measure	MD + D + G
converted effect size measure	OR + R + Z
required input data	See 'Section 21. From plot: means and dispersion (crude)'
	https://metaconvert.org/html/input.html

Examples

es_from_plot_means(
  n_exp = 35, n_nexp = 35,
  plot_mean_exp = 89, plot_mean_nexp = 104,
  plot_mean_sd_lo_exp = 109, plot_mean_sd_lo_nexp = 83,
  plot_mean_sd_up_exp = 69, plot_mean_sd_up_nexp = 125
)