effect_size_MB: Calculates HPS effect size

Description Usage Arguments Value Note References Examples

View source: R/HPS-ES-functions.R

Description

Calculates the HPS effect size estimator based on data from a multiple baseline design, as described in Hedges, Pustejovsky, & Shadish (2013). Note that the data must contain one row per measurement occasion per subject.

Usage

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effect_size_MB(outcome, treatment, id, time, phi, rho)

Arguments

outcome

Vector of outcome data. May not contain any missing values.

treatment

Vector of treatment indicators. Must be the same length as outcome.

id

factor vector indicating unique cases. Must be the same length as outcome.

time

vector of measurement occasion times. Must be the same length as outcome.

phi

Optional value of the auto-correlation nuisance parameter, to be used in calculating the small-sample adjusted effect size

rho

Optional value of the intra-class correlation nuisance parameter, to be used in calculating the small-sample adjusted effect size

Value

A list with the following components

g_dotdot total number of non-missing observations
K number of time-by-treatment groups containing at least one observation
D_bar numerator of effect size estimate
S_sq sample variance, pooled across time points and treatment groups
delta_hat_unadj unadjusted effect size estimate
phi corrected estimate of first-order auto-correlation
sigma_sq_w corrected estimate of within-case variance
rho estimated intra-class correlation
theta estimated scalar constant
nu estimated degrees of freedom
delta_hat corrected effect size estimate
V_delta_hat estimated variance of delta_hat

Note

If phi or rho is left unspecified (or both), estimates for the nuisance parameters will be calculated.

References

Hedges, L. V., Pustejovsky, J. E., & Shadish, W. R. (2013). A standardized mean difference effect size for multiple baseline designs across individuals. Research Synthesis Methods, 4(4), 324-341. doi:10.1002/jrsm.1086

Examples

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data(Saddler)
with(subset(Saddler, measure=="writing quality"), effect_size_MB(outcome, treatment, case, time))

data(Laski)
with(Laski, effect_size_MB(outcome, treatment, case, time))

jepusto/scdhlm documentation built on Aug. 23, 2018, 6:54 a.m.