NRFUopt: Sample sizes for a nonresponse follow-up study

In PracTools: Tools for Designing and Weighting Survey Samples

Sample sizes for a nonresponse follow-up study

Description

Compute optimal values of the first-phase sample size and the second-phase sampling fraction in a two-phase sample.

Usage

NRFUopt(Ctot=NULL, c1, c2, theta, CV0=NULL, CVpop=NULL, N=Inf, type.sw)

Arguments

Ctot	total variable cost
c1	cost per unit in phase-1
c2	cost per unit in phase-2
theta	probability of response for each unit
CV0	target coefficient of variation for the estimated total or mean
CVpop	Unit coefficient of variation
N	Population size; default is Inf
type.sw	type of allocation; "cost" = target total variable cost, "cv" = target coefficient of variation

Details

NRFUopt computes the optimal values of the first-phase sample size and the second-phase sampling fraction in a two-phase sample. Both stages are assumed to be selected using simple random sampling without replacement. If type.sw="cost", the optima are computed for a target total, expected cost across both phases. If type.sw="cv", the optima are computed for a target coefficient of variation for an estimated mean.

Value

List object with values:

allocation	type of allocation: either "fixed cost" or "fixed CV"
"Total variable cost"	expected total cost: fixed cost if type.sw="cost" or computed cost if type.sw="cv"; unrounded sample sizes are used in calculation
"Response rate"	first-phase response rate
CV	anticipated coefficient of variation (CV) if type.sw="cost" or target CV if type.sw="cv"
v.opt	optimal fraction of first-phase nonrespondents to select for second-phase follow-up
n1.opt	optimal number of units to sample at first-phase
"Expected n2"	expected number of respondents obtained at second-phase
"srs sample for same cv"	size of single-phase simple random sample (srs) needed to obtain same CV as the two-phase sample
"Cost Ratio: Two phase to srs"	ratio of expected cost for two-phase sample to cost of single-phase srs

Author(s)

Richard Valliant, Jill A. Dever, Frauke Kreuter

References

Saerndal, C.E., Swensson, B., and Wretman, J. (1992, examples 15.4.4 and 15.4.5). Model Assisted Survey Sampling. New York: Springer.

Valliant, R., Dever, J., Kreuter, F. (2018, chap.17). Practical Tools for Designing and Weighting Survey Samples, 2nd edition. New York: Springer.

Examples

    # optima for fixed target CV
NRFUopt(Ctot=NULL, c1=50, c2=200, theta=0.5, CV0=0.05, CVpop=1, type.sw = "cv")
    # optima for fixed total cost
NRFUopt(Ctot=100000, c1=50, c2=200, theta=0.5, CV0=NULL, CVpop=1, type.sw = "cost")

PracTools documentation built on Nov. 9, 2023, 9:06 a.m.