Intelligence and Achievement
Introduced| English | Meaning |
|---|---|
| intelligence quotient/ɪnˈtelɪdʒəns ˈkwəʊʃənt/ | intelligence quotient |
| mental age/ˈmentl eɪdʒ/ | mental age |
| chronological age/ˌkrɒnəˈlɒdʒɪkl eɪdʒ/ | chronological age |
| norm group/nɔːm ɡruːp/ | norm group |
| psychometric/ˌsaɪkəʊˈmetrɪk/ | psychometric |
| Reliability/rɪˌlaɪəˈbɪlɪti/ | The consistency of a measurement or assessment when repeated under comparable conditions. |
| validity/væˈlɪdɪti/ | How well a measure or study represents the concept or conclusion it is intended to address. |
| Standardisation/ˌstændədaɪˈzeɪʃn/ | Establishing or using consistent specifications, procedures or measures. |
| Flynn Effect/flɪn ɪˈfekt/ | Flynn Effect |
| Achievement tests/əˈtʃiːvmənt tests/ | Achievement tests |
| aptitude tests/ˈæptɪtjuːd tests/ | aptitude tests |
| fixed mindset/fɪkst ˈmaɪndset/ | fixed mindset |
| growth mindset/ɡrəʊθ ˈmaɪndset/ | growth mindset |
A number that has never had an agreed meaning
- Intelligence tests produce a precise-looking score.
- Yet the CED opens by saying consensus on how to define and measure intelligence remains elusive.
- Holding both facts at once is the whole skill in this topic.
What an IQ score is
- Early tests produced an intelligence quotient 智商 by dividing mental age 心理年龄 by chronological age 实际年龄 and multiplying by 100.
- Modern tests instead compare a person with a norm group 常模组.
- The number is a position in a distribution, not a quantity of a substance.

Intelligence test scores are standardised to a normal curve with mean 100 and SD 15
What makes a test sound
- All psychological assessments should follow sound psychometric 心理测量学 principles.
- Reliability 信度 means consistent results; validity 效度 means it measures what it claims.
- Standardisation 标准化 means the same procedure and a defined norm group every time.
Reliability, validity, or standardisation?
Sort each test property by the psychometric principle it names.
Select all the psychometric principles a sound assessment should meet.
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Popularity is not a psychometric property.
"Scores vary more within groups than between groups" is a statistical statement with a specific consequence: a group average tells you almost nothing about any individual in it. Quote the claim precisely — a vague gesture at "bias" does not earn the mark.
The worldwide rise in IQ scores over time is called the ____ Effect.
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The Flynn Effect is attributed to societal factors, not to changing biology.
The CED's statement that scores vary more within groups than between them implies that...
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Greater within-group variation is exactly why a group average cannot characterise a person.
How the scores have been misused
- IQ scores have risen worldwide over time — the Flynn Effect 弗林效应 — for societal reasons.
- Scores vary more within a group than between groups, so a group average explains almost nothing about an individual.
- Test scores have been used to limit access to jobs, military ranks and education — a documented misuse, not a hypothetical one.
An achievement test measures what someone already knows.
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Achievement looks backwards at knowledge; aptitude looks forward at predicted performance.
Match each mindset to what it assumes.
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Mindset is a belief about ability; an aptitude test is a prediction of it.
Achievement, aptitude and mindset
- Achievement tests 成就测验 measure what someone already knows; aptitude tests 能力倾向测验 predict future performance.
- A fixed mindset 固定型心态 treats intelligence as set from birth; a growth mindset 成长型心态 treats it as changeable through experience.
- The CED includes mindset because belief about ability affects the behaviour that produces ability.
Two students score identically on an aptitude test. One believes ability is fixed and stops after failing; the other believes it is malleable and revises her method. A year later their achievement differs — the mindset, not the score, predicted the outcome.
Intelligence has no agreed definition. An IQ is a position in a distribution, sound only if the test is reliable, valid and standardised. The Flynn Effect shows scores rise for social reasons, variation is greater within groups than between, and mindset shapes achievement independently of the score.
Write from a within-group spread of 30 points
- Two groups have mean scores of 100 and 103. Inside each group the scores spread across 30 points.
- Compare the mean gap with the spread inside a group.
Group means are 100 and 103, and scores inside each group spread across 30 points. Which difference is larger, and what does an IQ score represent?
103 minus 100 is 3. A 30-point range inside a group dwarfs that mean difference.
Which comparison is larger?
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30 is larger than 3. Group mean gaps can be smaller than the spread inside one group.