Preprocessing the predictor variables

Let's take a look at specific groups of predictor variables that commonly pop up in healthcare data.

Visit information

The first feature category in the ED2013 dataset contains information about the timing of the visit. Variables such as month, day of week, and arrival time are included here. Also included are the waiting time and length of visit variables (both in minutes).

Month

Let's analyze the VMONTH predictor in more detail. The following code prints all the values in the training set and their counts:

print(X_train.groupby('VMONTH').size())

The output is as follows:

VMONTH
01    1757
02    1396
03    1409
04    1719
05    2032
06    1749
07    1696
08    1034
09    1240
10    1306
11    1693
12    1551
dtype: int64

We can now see that the months are numbered from 01 to 12, as it says in the documentation, and that each month has representation.

One part of preprocessing the data is performing feature engineering – that is, combining or transforming the...