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The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): socio-demographic correlates, reliability, validity and some norms
Anthony Francis Jorm, P. A. Jacomb. Psychological Medicine, 1989-11-01
Topic: Risk, prevention and care in population studies
The IQCODE is a questionnaire which asks an informant about changes in an elderly person's everyday cognitive function. The questionnaire aims to assess cognitive decline independent of pre-morbid ability. In the present study, the IQCODE was administered to a sample of 613 informants from the general population. In addition, the questionnaire was administered to informants of 309 dementing subjects who had filled it out one year previously. A principal components analysis, using the general population sample, confirmed that the IQCODE measures a general factor of cognitive decline. The questionnaire was found to have high internal reliability in the general population sample (alpha = 0.95) and reasonably high test-retest reliability over one year in the dementing sample (r = 0.75). The total IQCODE score, as well as each of the 26-items, was found to discriminate well between the general population and dementing samples. The correlation with education was quite small (r = -0.13), indicating that contamination by premorbid ability is not a problem.
Why it matters
The IQCODE is a questionnaire that asks an informant about changes in an older person's everyday thinking. Given to 613 informants from the general population and to informants of 309 people with dementia, it showed high internal reliability, and its total score and each of its 26 items separated the two groups well. Scores had only a small correlation with education.
How this study scored 44/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / blinded because the record does not state it. We have no data on strength of evidence, so that was left out: it earned 42 of the 95 points we could judge it on, which is 44 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Psychological Medicine) |
| Journal's citation record | 3 / 4 | Psychological Medicine: journal h-index 331 (OpenAlex, 2026-10-29) |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | — / 5 | No evidence rating recorded — left out of this score |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 1989 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | 7 / 7 | Cited 1,120 times (OpenAlex, 2026-10-10) |
| Citations per year | 4 / 5 | 28.7 citations a year over 39 year(s) since 1989 |
| Impact for its field and year | 2 / 6 | Cited 2.7× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 0 / 6 | No other study in this library cites it |
| Still being cited | 3 / 4 | Cited 89 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 2 / 4 | Last-listed author P. A. Jacomb: h-index 32 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Australian National University: institution h-index 1,088 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 2594878) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 42 / 95 | Scored on 19 of 20 parts. We have no data for the rest, so they are left out: 42 of the 95 points we could judge it on is 44 out of 100. |
| Total | 44 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
APA 7th
Jorm, A. F., & Jacomb, P. A. (1989). The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): socio-demographic correlates, reliability, validity and some norms. Psychological Medicine. https://doi.org/10.1017/s0033291700005742
Vancouver
Jorm AF, Jacomb PA. The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): socio-demographic correlates, reliability, validity and some norms. Psychological Medicine. 1989. doi:10.1017/s0033291700005742. PMID: 2594878.
BibTeX
@article{jorm1989-2594878,
author = {Jorm, Anthony Francis and Jacomb, P. A.},
title = {{The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE): socio-demographic correlates, reliability, validity and some norms}},
journal = {Psychological Medicine},
year = {1989},
doi = {10.1017/s0033291700005742},
pmid = {2594878},
url = {https://doi.org/10.1017/s0033291700005742}
}
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