SPSbalan {USPS} | R Documentation |
Test for Conditional Independence of X-covariate Distributions from Treatment Selection within Given, Adjacent PS Bins.
xcvobj <- SPSbalan(dframe, trtm, qbin, xvar, faclev=3)
dframe |
Name of augmented data.frame written to the appn="" argument of SPSlogit(). |
trtm |
Name of the two-level treatment factor variable. |
qbin |
Name of variable containing bin numbers. |
xvar |
Name of one baseline covariate X variable used in the SPSlogit() PS model. |
faclev |
Maximum number of different numerical values an X-covariate can assume without automatically being converted into a "factor" variable; faclev=1 causes a binary indicator to be treated as a continuous variable determining a proportion. |
The second step in Supervised Propensity Scoring analyses is to verify that baseline X-covariates have the same distribution, regardless of treatment, within each fitted PS bin.
An output list object of class SPSbalan.
"contin"uous xvar => only the following four outputs...
aovdiff |
ANOVA output for marginal test. |
form2 |
Formula for differences in X due to bins and to treatment nested within bins. |
bindiff |
ANOVA output for the nested within bin model. |
df3 |
Output data.frame containing 3 variables: X-covariate, treatment and bin. |
factab |
Marginal table of counts by X-factor level and treatment. |
tab |
Three-way table of counts by X-factor level, treatment and bin. |
cumchi |
Cumulative Chi-Square statistic for interaction in the three-way, nested table. |
cumdf |
Degrees of-Freedom for the Cumulative Chi-Squared. |
Bob Obenchain <wizbob@att.net>
Cochran WG. (1968) The effectiveness of adjustment by subclassification in removing bias in observational studies. Biometrics 24: 205-213.
Obenchain RL. (2009) USPSinR.pdf ../R_HOME/library/USPS 40 pages.
Rosenbaum PR, Rubin RB. (1983) The Central Role of the Propensity Score in Observational Studies for Causal Effects. Biometrika 70: 41-55.
Rosenbaum PR, Rubin DB. (1984) Reducing Bias in Observational Studies Using Subclassification on a Propensity Score. J Amer Stat Assoc 79: 516-524.
SPSlogit
, SPSnbins
and SPSoutco
.
data(lindner) PStreat <- abcix~stent+height+female+diabetic+acutemi+ejecfrac+ves1proc logtSPS <- SPSlogit(lindner, PStreat, PSfit, PSrnk, PSbin, appn="lindSPS") SPSbalvs <- SPSbalan(lindSPS, abcix, PSbin, ves1proc) SPSbalvs plot(SPSbalvs)