The alternative strategy, categorizing time on ART [ 2, 10– 15, 15, 43, 49, 50], produces risk estimates that change abruptly, making them biologically implausible [ 14], and may poorly represent the underlying data.
Time was also a limitation factor in constructing the score, because exposure time was categorized in a subjective way, trying to categorize time as homogeneously as possible.
We categorized time since immigration to Ontario as recent (i.e. ≤ 5 years) or non-recent (i.e. >5 years).
Briefly, animals had to categorize time intervals as either long or short by making left/right choices.
Due to the small number of subjects, samples were grouped according to two categorized time periods: early (baseline to 3 months) and late (>6 months following disease onset).
32 To assess whether the length of time a ban was in place was influential, subsequent models categorized time since implementation of bans with cut points at the 25th centile (0 years), 50th centile (4 years), and 75th centile (9 years) and adjusted for sex, calendar year, and state smoking rates.
58 In the case of non-proportionality, interactions with a categorized time variable based on clinical follow-up intervals (< day 14, days 14 21, 21 28, and > day 28) were used to account for changing effects over time, and neighboring windows with similar effects of genetic covariates as determined by Wald test were merged.
Others have categorized time-signal intensity curve shapes and correlated them with breast lesion types[ 28].
However, categorizing the time axis into blocks of time effectively removes an important variable describing outcomes in the dynamic process of treatment, namely the continuity of change over time.
Instead of categorizing the time between surgeries into four groups we also investigated the time interval between the two THA procedures in each patient as a continuous variable.
These choices can be categorized as Time Assets or Time Debts, which are two concepts I learned from Patrick McKenzie.
