es_from_cases_time {metaConvert}

Convert the number of cases and the person-time of disease-free observation in two independent groups into an incidence rate ratio (IRR)

Description

Convert the number of cases and the person-time of disease-free observation in two independent groups into an incidence rate ratio (IRR)

Usage

es_from_cases_time(n_cases_exp, n_cases_nexp, time_exp, time_nexp, reverse_irr)

Arguments

n_cases_exp

number of cases in the exposed group

n_cases_nexp

number of cases in the non-exposed group

time_exp

person-time of disease-free observation in the exposed group

time_nexp

person-time of disease-free observation in the non-exposed group

reverse_irr

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

Details

This function estimates the incidence rate ratio from the number of cases and the person-time of disease-free observation in two independent groups.

The formula used to obtain the IRR and its standard error are (Cochrane Handbook (section 6.7.1):

logirr = log(\frac{n\_cases\_exp / time\_exp}{n\_cases\_nexp / time\_nexp)}

logirr\_se = \sqrt{\frac{1}{n\_cases\_exp} + \frac{1}{n\_cases\_nexp}}

Value

This function estimates IRR.

natural effect size measure	IRR
converted effect size measure	N/A
required input data	See 'Section 5. Incidence Ratio Ratio'
	https://metaconvert.org/html/input.html

References

Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.3 (updated February 2022). Cochrane, 2022. Available from www.training.cochrane.org/handbook.

Examples

es_from_cases_time(
  n_cases_exp = 241, n_cases_nexp = 554,
  time_exp = 12.764, time_nexp = 19.743
)