Turning personality into something you can measure

1. To compare one person with another, psychologists need personality recorded in a form that can be written down and worked with.
2. A personality scale gives you a score showing how much of a characteristic you have.
3. A personality type puts you into a category alongside everyone else who answered in a similar way.
4. Both usually begin from the same thing, a set of questions you answer about yourself, so the real difference lies in what is done with your answers afterwards.

Personality scales

1. A scale treats a characteristic as a continuous line running from very little of it at one end to a great deal of it at the other.
2. You work through a set of statements and choose a point on a rating line for each one, from strong disagreement through to strong agreement.
   1. Each choice is given a number, and the numbers are added up to produce your score on that characteristic.
3. Your score places you somewhere along the line rather than at one end of it, so a person who comes out near the middle is recorded as being near the middle.
4. Because the score is graded, small differences between two people still show up, and any score can be set against the average for a large group.
5. A scale also lets change be tracked, because the same person can be measured again later and the two scores compared.

Personality types

1. A type is a category, so the measure sorts you into one group or another instead of placing you on a line.
2. The categories are meant to be distinct, which means you are counted as being in one of them and not partly in both.
3. Types are quick to grasp and easy to report, which is why they turn up in everyday settings such as careers advice.
4. The cost is detail, because two people placed in the same category can be quite different from each other.
   1. Someone sitting just on the boundary is recorded as fully one thing, which loses the fact that they were borderline.

Where each one is useful

1. Research that needs to compare groups carefully tends to use scales, because graded scores can be averaged and analysed.
2. Settings that need a short, memorable summary tend to use types, because a label is easier to act on than a number.
3. Both depend on you reporting on yourself honestly, so answers given to look good weaken the validity of whatever comes out.
4. Both are also limited to the questions asked, so anything the questions do not cover simply does not appear in the result.

Turning this into marks

1. Say that a scale gives a score along a range and a type sorts you into a category, then add a short example.
2. On an applied item, name which of the two a described measure is and quote the wording that told you.
3. The mark most often lost is writing about scales only when the question asks you to compare the two.