Standard Score vs Scaled ScoreScaled score and Standard score. There is a lot of confusion with these two concepts and to understand the difference we need to know how are they made.
The 3 Characteristics of Scaled Score vs Standard Score: 1) A Standard Score and a Scaled Score are both scores that we obtain from the transformation of another score (normally raw scores). 2) However, a Standard Score will follow a normal distribution, also known as bell curve or Gaussian distribution. 3) On the other hand, a Scaled Score doesn't have to follow a normal distribution. On the picture below we can see a Standard Score vs Scaled Score distributions. The Standard Score distribution follows the shape of a bell. The Scaled Score distribution doesn't have to. On this picture, the Scaled Score distribution follows a random distribution. 
Scaled Score
to Standard Score CONVERSION
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Standard Score Distribution

Scaled Score Distribution

Standard Score Distribution

Scaled Score Distribution

EXAMPLE:
Let's say that student A gets a 96 in a given test. And student B, gets a 93 in a different test. If we compare them, we might jump to the conclusion that student A had a better performance. But since we don't know the difficulty of both tests we can't be sure of that. What we do, is to transform both scores into a one new scale that takes into consideration the difficulty of both tests. We get the two raw scores (93 and 96) and we transform them into new standardized ones. We apply certain operations on those numbers and then obtain that student A got a 94 in our new scale, and that student B got a 94 as well. We get then to the conclusion that both students actually had the same level of performance, because if take into consideration both scores and tests difficulty that's what we get. 