meta: or2smd – R documentation

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or2smd

Conversion from log odds ratio to standardised mean difference

Description

Conversion from log odds ratio to standardised mean difference using method by Hasselblad & Hedges (1995) or Cox (1970).

Usage

or2smd(
  lnOR,
  selnOR,
  studlab,
  data = NULL,
  subset = NULL,
  exclude = NULL,
  method = "HH",
  ...
)

Arguments

`lnOR`	Log odds ratio(s) or meta-analysis object.
`selnOR`	Standard error(s) of log odds ratio(s) (ignored if argument `lnOR` is a meta-analysis object).
`studlab`	An optional vector with study labels (ignored if argument `lnOR` is a meta-analysis object).
`data`	An optional data frame containing the study information (ignored if argument `lnOR` is a meta-analysis object).
`subset`	An optional vector specifying a subset of studies to be used (ignored if argument `lnOR` is a meta-analysis object).
`exclude`	An optional vector specifying studies to exclude from meta-analysis, however, to include in printouts and forest plots (ignored if argument `lnOR` is a meta-analysis object).
`method`	A character string indicating which method is used to convert log odds ratios to standardised mean differences. Either `"HH"` or `"CS"`, can be abbreviated.
`...`	Additional arguments passed on to `metagen` (ignored if argument `lnOR` is a meta-analysis object).

Details

This function implements the following methods for the conversion from log odds ratios to standardised mean difference:

Hasselblad & Hedges (1995) assuming logistic distributions (method == "HH")
Cox (1970) and Cox & Snell (1989) assuming normal distributions (method == "CS")

Internally, metagen is used to conduct a meta-analysis with the standardised mean difference as summary measure.

Argument lnOR can be either a vector of log odds ratios or a meta-analysis object created with metabin or metagen and the odds ratio as summary measure.

Argument selnOR is mandatory if argument lnOR is a vector and ignored otherwise. Additional arguments in ... are only passed on to metagen if argument lnOR is a vector.

Value

An object of class "meta" and "metagen"; see metagen.

Author(s)

Guido Schwarzer sc@imbi.uni-freiburg.de

References

Borenstein M, Hedges LV, Higgins JPT, Rothstein HR (2009): Introduction to Meta-Analysis. Chichester: Wiley

Cox DR (1970): Analysis of Binary Data. London: Chapman and Hall / CRC

Cox DR, Snell EJ (1989): Analysis of Binary Data (2nd edition). London: Chapman and Hall / CRC

Hasselblad V, Hedges LV (1995): Meta-analysis of screening and diagnostic tests. Psychological Bulletin, 117, 167–78

Examples

# Example from Borenstein et al. (2009), Chapter 7
#
mb <- or2smd(0.9069, sqrt(0.0676))
# TE = standardised mean difference (SMD); seTE = standard error of SMD
data.frame(SMD = round(mb$TE, 4), varSMD = round(mb$seTE^2, 4))

# Use dataset from Fleiss (1993)
#
data(Fleiss1993bin)
m1 <- metabin(d.asp, n.asp, d.plac, n.plac,
              data = Fleiss1993bin,
              studlab = paste(study, year),
              sm = "OR", comb.random = FALSE)
or2smd(m1)