OMbook_glossary

N

Non-inferiority trials/studies

These are extensions of the more conventional randomised controlled trials which usually seek to find...

Numeracy

OK this not a normal entry, it's a cry from the heart! Details So numeracy is ability...

Number Needed to Treat (NNT) and Number Needed to Harm (NNH)

These are very simple ideas coming out of the randomised controlled trial (RCT) world and...

NPV (Negative Predictive Value)

Crucial parameter of any simple screening design: the probability that someone scoring below the screening...

Non-parametric "tests"

Really "non-parametric statistical methods". Statistical methods that don't rely on assumptions about population distributions,...

Null hypothesis significance testing (NHST) paradigm

This, essentially the same as "inferential testing" (q.v.), is the paradigm which has dominated the...

Null hypothesis

This is one of the fundamental building blocks of the "Null Hypothesis Significance Test" (NHST)...

n > 5 rule

See anonymisation!

Notched box plot

[Go to the entry about box plots before this if you are not familiar with...

Nested data, nesting

Very often therapy change data is "nested": sessional observations within each client, each client within...

Nocebo effect

See Placebo effect.

Nomothetic measures, Nomothetic data

Nomothetic measures are ones on which everyone has a value that can be compared with...