In simple terms
A prognosis is a forecast, not a verdict. It is a medically informed prediction about the likely outcome of a condition.
It answers a different question from a diagnosis. Diagnosis names what the problem is. Prognosis estimates where it is heading.
How it works
Clinicians weigh several things: the type of condition, how far it has advanced at diagnosis, genetic features, the person’s general health and age, what treatments exist, and how the person responds to them.
Much of the estimate comes from population data rather than the individual. A five year survival rate describes how many people with the same diagnosis were alive five years later. It does not say what will happen to one person.
Prognoses are often given in words rather than numbers, such as excellent, good, fair or poor. A guarded prognosis means there is not yet enough information to predict.
Accuracy is limited, and known to be. A systematic review of 42 studies in palliative care found clinicians’ survival predictions were between 23 and 78 percent accurate, and that overestimates were more common than underestimates.
Why it matters
Prognosis shapes real decisions: whether to start an aggressive treatment, when to involve palliative care, and how people plan their lives and finances.
Because the estimate carries real uncertainty, it is usually offered as a range rather than a single figure, and revisited as the picture changes.
Where you’ll see it
- Clinic letters and discharge summaries
- Cancer survival statistics
- Insurance and benefits assessments
- Research comparing treatments over time
Example
A clinician may say a cancer found early has a good prognosis, meaning most people with that stage and type do well, while still being unable to promise any one outcome.
Often confused with
Prognosis is not diagnosis. It is also not a life expectancy figure for one person, because survival statistics describe groups.
Key facts
- A prognosis is a medically informed prediction about the likely outcome of a condition, covering both the chance of recovery and how the condition may unfold over time.1
- Prognostic factors include the type of condition, how advanced it is at diagnosis, genetic characteristics, overall health, available treatments, response to treatment and age.1
- Clinicians often describe a prognosis as excellent, good, fair or poor, and a guarded prognosis means there is not enough information to predict.1
- A systematic review of 42 studies and more than 12,000 estimates found clinicians' categorical survival predictions in palliative care were between 23 and 78 percent accurate.2
- In that review 13 studies showed clinicians overestimated median survival and 5 showed underestimates.2
This entry explains a medical term. It is not medical advice. If you are concerned about your health, speak with a qualified health professional.
Related concepts
In the news
Quick checkWhat does a five year survival rate actually describe?Show answer
A group: how many people with the same diagnosis were alive five years later, not one person's outcome.
Sources
- Cleveland Clinic. Prognosis. 2 December 2024 (accessed 22 September 2026)
- White N and colleagues, PLOS ONE. A Systematic Review of Predictions of Survival in Palliative Care: How Accurate Are Clinicians and Who Are the Experts?. 25 August 2016 (accessed 22 September 2026)
Editorially reviewed by Specialty Digest Editorial TeamLast reviewed September 22, 2026Researched and drafted with AI assistanceReport an issue