Combine V15a/c logic properly for survey Wave 12

[nmdefries]

Description

Since items V15a and V15c won't be available at the same time for a given data file, combine their if blocks into one so that only one of the conditions is triggered per data file.

Changelog

• variables.R: Change if blocks that depend on item V15c (if ( all(c("V15c", "V15b") %in% names(input_data)) ) and if ( "V15c" %in% names(input_data) )) to else if.

Fixes

error introduced in #1303.

When item V15a exists, as in Wave 11 data, vaccine_barrier_* and vaccine_barrier_*_has fields were created in an initial if block. A second if block checked for the existence of item V15c (replacing V15a as of Wave 12) and if not found, overwrote those fields with NA. Since the existence of V15a and V15c were checked separately, the V15c else condition was always triggered, resulting in the vaccine_barrier_* and vaccine_barrier_*_has fields always being completely missing for pre-Wave 12 survey versions and the relevant indicators not being reported.

We'll need to reissue the smoothed_wvaccine_barrier_* and smoothed_wvaccine_barrier_*_has indicators back to Dec 12.

[capnrefsmmat]

Good catch. I think this makes sense now, although it may be good to add more explicit code comments to explain which items are in which waves:

Wave	V15a	V15b	V15c
11	Yes	Yes	No
12	No	Yes	Yes