convert_d2or {esc}

Convert effect size d into OR

Description

Compute effect size OR from effect size d.

Usage

convert_d2or(
  d,
  se,
  v,
  totaln,
  es.type = c("logit", "cox"),
  info = NULL,
  study = NULL
)

Arguments

d

The effect size d.

se

The standard error of d. One of se or v must be specified.

v

The variance of d. One of se or v must be specified.

totaln

A vector of total sample size(s).

es.type

Type of effect size odds ratio that should be returned. May be es.type = "logit" or es.type = "cox" (see 'Details').

info

String with information on the transformation. Used for the print-method. Usually, this argument can be ignored

study

Optional string with the study name. Using combine_esc or as.data.frame on esc-objects will add this as column in the returned data frame.

Details

Conversion from d to odds ratios can be done with two methods:

es.type = "logit"

uses the Hasselblad and Hedges logit method.

es.type = "cox"

uses the modified logit method as proposed by Cox. This method performs slightly better for rare or frequent events, i.e. if the success rate is close to 0 or 1.

Value

The effect size es, the standard error se, the variance of the effect size var, the lower and upper confidence limits ci.lo and ci.hi, the weight factor w and the total sample size totaln.

Note

Effect size is returned as exp(log_values) (odds ratio), confidence intervals are also exponentiated. To get the log-values, use convert_d2logit. However, variance and standard error of this function are returned on the log-scale!

References

Lipsey MW, Wilson DB. 2001. Practical meta-analysis. Thousand Oaks, Calif: Sage Publications

Wilson DB. 2016. Formulas Used by the "Practical Meta-Analysis Effect Size Calculator". Unpublished manuscript: George Mason University

Cox DR. 1970. Analysis of binary data. New York: Chapman & Hall/CRC

Hasselblad V, Hedges LV. 1995. Meta-analysis of screening and diagnostic tests. Psychological Bulletin 117(1): 167–178. doi: 10.1037/0033-2909.117.1.167

Borenstein M, Hedges LV, Higgins JPT, Rothstein HR. 2009. Introduction to Meta-Analysis. Chichester, West Sussex, UK: Wiley

Examples

# d to odds ratio
convert_d2or(0.7, se = 0.5)
# odds ratio to d
convert_or2d(3.56, se = 0.91)