NRFUopt | R Documentation |
Compute optimal values of the first-phase sample size and the second-phase sampling fraction in a two-phase sample.
NRFUopt(Ctot=NULL, c1, c2, theta, CV0=NULL, CVpop=NULL, N=Inf, type.sw)
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 |
type.sw |
type of allocation; |
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.
List object with values:
allocation |
type of allocation: either "fixed cost" or "fixed CV" |
"Total variable cost" |
expected total cost: fixed cost if |
"Response rate" |
first-phase response rate |
CV |
anticipated coefficient of variation (CV) if |
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 |
Richard Valliant, Jill A. Dever, Frauke Kreuter
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.
# 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")
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