Tools

Cognitive Failures Questionnaire (CFQ)

Broadbent's 25-item measure of everyday memory, attention, and action slips: the standard brain fog questionnaire

Brain fog is one of the most common complaints in long COVID and ME/CFS, and one of the hardest to put a number on. The Cognitive Failures Questionnaire, published by Donald Broadbent and colleagues in 1982, is a widely used self-report measure of everyday cognitive lapses: forgetting why you walked into a room, reading a paragraph and taking nothing in, losing your thread mid-sentence. You rate how often 25 such lapses have happened over the past six months, from 0 (never) to 4 (very often), for a total of 0–100.

Community samples have averaged in the low 30s. Groups with long COVID have averaged from the mid-40s to the 60s, and one ME/CFS sample averaged 57. The questionnaire does not measure cognitive performance (scores are only weakly linked to objective testing, if at all), but it does capture how often lapses happen, which is what most people mean by brain fog and what clinicians rarely have a number for. The results also show the three overlapping item groups from a published analysis, forgetfulness, distractibility and false triggering, as a rough guide to where lapses cluster.

The questionnaire is presented in two pages of 12–13 items. If mental fatigue rather than lapses is your main concern, the Chalder Fatigue Scale has a mental fatigue subscale, and the DSQ-PEM characterises symptoms that worsen after cognitive effort.

This is not a diagnostic tool. The CFQ records self-reported lapses; it does not assess cognitive function and cannot diagnose cognitive impairment or any condition. Scores rise with fatigue, stress, and low mood as well as with neurological causes. Discuss your results with your doctor. Based on: Broadbent DE, Cooper PF, FitzGerald P, Parkes KR. The Cognitive Failures Questionnaire (CFQ) and its correlates. Br J Clin Psychol. 1982;21(1):1–16. The questionnaire is the work of its authors; this page is an interactive scoring aid for personal, non-commercial use.
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The following questions are about minor mistakes which everyone makes from time to time, but some of which happen more often than others. We want to know how often these things have happened to you in the past 6 months.

1. Do you read something and find you haven't been thinking about it and must read it again?

2. Do you find you forget why you went from one part of the house to the other?

3. Do you fail to notice signposts on the road?

4. Do you find you confuse right and left when giving directions?

5. Do you bump into people?

6. Do you find you forget whether you've turned off a light or a fire or locked the door?

7. Do you fail to listen to people's names when you are meeting them?

8. Do you say something and realise afterwards that it might be taken as insulting?

9. Do you fail to hear people speaking to you when you are doing something else?

10. Do you lose your temper and regret it?

11. Do you leave important letters unanswered for days?

12. Do you find you forget which way to turn on a road you know well but rarely use?

13. Do you fail to see what you want in a supermarket (although it's there)?

Understanding your Cognitive Failures Questionnaire score

What the score measures

The Cognitive Failures Questionnaire (CFQ) was published by Donald Broadbent and colleagues in 1982. It asks how often 25 everyday slips of attention, memory and action happen to you, each rated from 0 (never) to 4 (very often), for a total from 0 to 100. Higher scores mean more frequent lapses. It is widely used in research on brain fog after COVID-19 and in ME/CFS.

The forgetfulness, distractibility and false triggering figures follow the three factors described by Rast et al. 2009, in which many items count towards two factors. An analysis of 839 adults found these factors so closely related that the total fitted best, and advised against subscales (Goodman et al. 2022). Treat them as a rough guide.

Score bands

There are no official cut-offs. A US community sample of 839 adults averaged 31.7, and UK adults who had never had COVID-19 averaged 32.7. Groups with long COVID have averaged between 44 and 64, and one group with ME/CFS 57. Some studies treat a score above 43 as high, but that is a research convention, not a validated threshold.

Average CFQ totals in published studies (number of people in brackets)
GroupAverageSource
Irish adults who had COVID-19 without lasting symptoms (50)25.9Holland et al. 2024
US community adults (839)31.7Goodman et al. 2022
UK adults who had never had COVID-19 (53)32.7Bland et al. 2024
UK adults with post-COVID syndrome (50)44.4Bland et al. 2024
Irish post-COVID clinic patients (71)50.2Holland et al. 2024
People with ME/CFS (87)57.4Attree et al. 2014
Danish long COVID clinic patients (182)63.5Miskowiak et al. 2023

The studies used different recall periods, so compare loosely.

What a change in score means

No minimal important change has been published for the CFQ. It behaves like a stable trait: when adults were retested two years apart, their totals correlated at 0.71. This version asks about the past six months, so it moves slowly. Compare results taken several months apart and look for a steady trend rather than one difference.

Broadbent's team also found scores stable over long periods (Broadbent et al. 1982). With no published figure, one Dutch study used a 10-point change as its own threshold (Berentschot et al. 2025): a reasonable rule of thumb, not a validated one.

What it does not measure

Not necessarily. The CFQ records how often you notice everyday slips, not how well you do on tests. In studies including people after COVID-19, CFQ scores were weakly linked or not linked to objective test results, and rose with fatigue, stress and low mood. A high score is a valid record of what you live with, but it is not a test of cognitive function.

It does not measure mental fatigue or what thinking costs you afterwards: see the Chalder Fatigue Scale, the DSQ-PEM and the post-exertional malaise explainer.

Taking this to your GP or consultant

Bring the total, the date and the trend from your saved results. Describe the CFQ as a validated 25-question measure of how often everyday lapses happen, widely used in long COVID research, and give two or three examples that matter, such as missed appointments or medication mistakes. It can support a request for a cognitive assessment or work adjustments; it cannot show the cause or confirm impairment. See also preparing for a GP appointment.

Sources