es_from_2x2_prop function

Convert the proportion of occurrence of a binary event in two independent groups into several effect size measures

es_from_2x2_prop(
  prop_cases_exp,
  prop_cases_nexp,
  n_exp,
  n_nexp,
  table_2x2_to_cor = "tetrachoric",
  reverse_prop
)

Arguments

• prop_cases_exp: proportion of cases/events in the exposed group (ranging from 0 to 1)
• prop_cases_nexp: proportion of cases/events in the non-exposed group (ranging from 0 to 1)
• n_exp: total number of participants in the exposed group
• n_nexp: total number of participants in the non exposed group
• table_2x2_to_cor: formula used to obtain a correlation coefficient from the contigency table (see details).
• reverse_prop: a logical value indicating whether the direction of generated effect sizes should be flipped.

Returns

This function estimates and converts between several effect size measures.

natural effect size measure	OR + RR + NNT
converted effect size measure	D + G + R + Z
required input data	See 'Section 7. Contingency (2x2) table or proportions'
	https://metaconvert.org/input.html

Details

This function uses the proportions and sample size to recreate the 2x2 table, and then relies on the calculations of the es_from_2x2_sum() function.

The formulas used is to obtain the 2x2 table are

$$n\_cases\_exp = prop\_cases\_exp * n\_exp$$ $$n\_cases\_nexp = prop\_cases\_nexp * n\_nexp$$ $$n\_controls\_exp = (1 - prop\_cases\_exp) * n\_exp$$ $$n\_controls\_nexp = (1 - prop\_cases\_nexp) * n\_nexp$$

Examples

es_from_2x2_prop(prop_cases_exp = 0.80, prop_cases_nexp = 0.60, n_exp = 10, n_nexp = 20)