recode_missing_visits {CTNote}R Documentation

Recode Missing or Ambiguous UDS in a Subject Use Pattern


Replace all missing UDS "o" in a use pattern string


  missing_is = "o",
  missing_becomes = c("+", "", "-")



A character string showing the daily, by visit, or weekly substance use pattern for a single subject


Which single character is used to mark missing UDS in a use pattern string? Defaults to "o".


How should missing UDS be treated? Defaults to marking the subject as positive for that missing period. Options are "+" for positive, "" for ignore, or "-" for negative (note that this last option should only be used in case where the "missing" UDS is a regular and expected artefact of the study design and the preceding and following UDS are both negative).


At current, we allow for many symbols in the use pattern "word", such as "_" for missing by study design, "o" missing for protocol non-compliance (the most common form of missing), "+" for positive, "-" for negative, and "*" for mixed positive and negative results (this usually comes up when the visit represents multiple days and there are both positive and negative results in those days; for example, a subject is tested weekly; they provided a positive test on Tuesday but came back to provide a negative test the following day).


A character string with all missing UDS values (marked as "o" unless a different value is supplied to missing_is) replaces by the value supplied to missing_becomes.


  pattern_char <- "__++++*o-------+--+-o-o-o+o+"
  # Default: change all missing weeks to positive
  # Other example: remove all weeks with no UDS by design
  recode_missing_visits(pattern_char, missing_is = "_", missing_becomes = "")

[Package CTNote version 0.1.0 Index]