In this post you will understand how ETS converts rubric scores to scaled scores in the Writing section.
The Writing section contains two questions/essays, and each one is scored from 0.0 to 5.0 points with an interval of 0.5 points. That means that you can score 4.5 or a 4.0 in one of the questions, but you can’t get a 4.25.
For example, lets say you obtain the following set of results: [4.5,4]. Then, they calculate the average (sum of the the two scores divided by number of elements):
(4.5 + 4) /2 = 9.5 / 2 = 4.25
and the outcome (4.25) is converted to a 30 points scale. See the following table:
To learn which are the scoring standards for each question check this link: Writing standards