Understand the relationship
The reasoning behind the result
Follow the original seedlings
The denominator is the defined seedling cohort at the start of follow-up. New seedlings added later do not belong in its numerator. Survival is assessed at the entered follow-up point rather than inferred from a growth measurement.
The calculator does not choose a criterion for survival, infer causes of loss or assess whether conditions were appropriate. Those are separate observations and experimental decisions.
Known outcomes and full-cohort bounds
Confirmed survivors divided by assessed outcomes gives a known-status fraction. If missing follow-up is related to outcome, that fraction may not represent the complete cohort.
Logical bounds retain all original seedlings: count unknowns as non-survivors for the lower bound and as survivors for the upper bound. They show the consequence of missing status without assuming its cause.
A descriptive fraction is not a treatment comparison
Counts may be pooled across cohorts only when that total has an intended interpretation. Unequal cohort sizes require count weighting. Individual rows stay visible so an aggregate does not hide a different pattern in one cohort.
No statistical significance, future survival probability, disease diagnosis or care recommendation is inferred. Study design and suitable analysis are needed for causal claims.
Follow the numbers
Forty survivors and five unknowns
- Start with 50 seedlings. Five have unknown follow-up, leaving 45 assessed.
- Forty confirmed survivors give 40/45 = 88.8889% among assessed seedlings.
- The complete cohort's fraction is bounded by 40/50 = 80% and 45/50 = 90%.
The assessed share and full-cohort bounds answer different questions and are shown together.
Quick guide
How to use this calculator
- Enter the assessment period and each group's initial seedlings.
- Record confirmed confirmed surviving seedlings separately from unknown outcomes.
- Read the assessed denominator and the full-cohort bounds before comparing percentages.
- Pool only cohorts whose observation period and outcome definition make a combined fraction meaningful.
Calculation method
Calculation and interpretation
Describe seedling survival at an entered follow-up point with the outcome denominator made explicit.
Assessed = initial − unknown; observed fraction = confirmed/assessed; whole-cohort bounds = confirmed/initial to (confirmed + unknown)/initial
Worked example
Forty survivors and five unknowns
The assessed share and full-cohort bounds answer different questions and are shown together.
Assessed = initial − unknown; observed fraction = confirmed/assessed; whole-cohort bounds = confirmed/initial to (confirmed + unknown)/initial
Supported inputs
Precision and limits
Descriptive cohort records
A recorded fraction does not establish a biological cause or predict an individual's outcome. Keep counting definitions, observation period and missing-status rules consistent. No treatment, husbandry or management action is prescribed.
Unknown outcomes are not failures
The assessed fraction excludes unknown status. The full-cohort bounds show the possible fraction if all unknowns were non-events or all were events; they are logical bounds, not a statistical confidence interval.
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