Thursday, March 8, 2012

Creating Variables: Days Between Application Date and Term Start

Hello everybody! This post will be a continuation of the Creating Variables series. Today we’ll be discussing how and why to create a “days between application date and term start” variable.

At first glance, this variable seems a little long-winded, but I can assure you, it’s worth its weight in characters. As you all know, for any institution that accepts applications on a non-rolling basis, there exists a window of time during which applications must be filed to be considered for acceptance. The amount of time between when an application is submitted and when the relevant admission term begins can be an indication of a student’s interest in a particular institution. For example, a student may turn in an application to his first-choice college during the first week that applications are accepted, but this same student might wait until the day or week before the deadline to turn in applications to his safety or back-up schools. In this way, the amount of time between the day that a student turns in an application and the term start date can be seen as an indicator of that student’s interest. Let’s go ahead and calculate this:

The first step is to hook applicant data into a transform node:

Next, after opening the transform node, we’ll need to select the “Days Between” formula from the drop-down menu:

In the “Enter a Formula” window, we’ll want to enter:

…Where ‘[A]’ corresponds to the variable in your dataset that represents the date each application was submitted, ‘09/01/2012’ represents the start date for the term you’re admitting for, and “date” is actually the date function from the formula drop-down menu:

Before naming and saving this new variable, be sure to switch the “Result Type” to “integer”:

And, voila! Now you have a “days between application date and term start variable” to add to your predictive variable arsenal.

-Caitlin Garrett, Statistical Analyst at Rapid Insight


  1. Why would you want the number of days to be returned as text? For analysis shouldn't it be an integer?

    1. You're right - the resulting data type should be integer, not text. That was a typo and the entry has been updated accordingly. Thanks for bringing this to my attention!