Compute Cronbach's alpha coefficient of reliability from survey data. The formula is equation (2) of Cronbach (1951) only with design-based estimates of the variances.
svycralpha(formula, design, na.rm = FALSE)
One-sided formula giving the variables that make up the total score
survey design object
TRUE to remove missing values
Cronbach LJ (1951). "Coefficient alpha and the internal structure of tests". Psychometrika. 16 (3): 297-334. doi:10.1007/bf02310555.