Replication Requirement Calculator
Estimates per-group replication for a two-mean target effect. The form displays ceil((z+power-z)^2 × 2 × (SD/effect)^2) beside replication requirement, using a worked condition that can be recalculated with the labeled inputs.
Set the labeled inputs
Replication Requirement
Scope of the replication requirement method
The replication requirement page estimates per-group replication for a two-mean target effect.
Replication Requirement is limited to the statistical quantity named by the result panel. The replication requirement calculation does not silently add a population, time horizon, causal direction, or decision threshold that is absent from the fields.
How the inputs shape replication requirement
- Critical z: For replication requirement, the worked value for critical z is 1.96. Treat the critical z entry (1.96) explicitly as a count, proportion, rate, estimate, or model parameter before comparing replication requirement conditions. The form enforces minimum 0.
- Power z: For replication requirement, the worked value for power z is 0.84. Treat the power z entry (0.84) explicitly as a count, proportion, rate, estimate, or model parameter before comparing replication requirement conditions. The form enforces minimum 0.
- Standard deviation: For replication requirement, the worked value for standard deviation is 10 units. Treat the standard deviation entry (10 units) explicitly as a count, proportion, rate, estimate, or model parameter before comparing replication requirement conditions. The form enforces minimum 1e-06.
- Target effect: For replication requirement, the worked value for target effect is 5 units. Treat the target effect entry (5 units) explicitly as a count, proportion, rate, estimate, or model parameter before comparing replication requirement conditions. The form enforces minimum 1e-06.
The entries used for replication requirement must refer to one coherent analysis condition. Combining incompatible populations, periods, or measurement definitions can produce valid replication requirement arithmetic for a nonexistent study.
The arithmetic used for replication requirement
For replication requirement, match every symbol in the relationship to a labeled field before substituting numbers. Replication Requirement is reported in the scale implied by the inputs and formula.
While checking replication requirement, inspect every denominator in ceil((z+power-z)^2 × 2 × (SD/effect)^2). For replication requirement, a zero or near-zero denominator can make replication requirement undefined or unstable.
The surrounding workflow may also require randomization block size.
A reproducible replication requirement case
The default replication requirement condition is Critical z = 1.96, Power z = 0.84, Standard deviation = 10 units, Target effect = 5 units.
SD 10, effect 5, z values 1.96 and .84 require about 63 observations per group.
The live calculator reports Required observations 63. Repeating one intermediate step from ceil((z+power-z)^2 × 2 × (SD/effect)^2) provides a fixed replication requirement reference check for later code changes.
Conditions attached to replication requirement
This planning approximation assumes equal groups, known design variance, and a two-sided normal threshold.
For replication requirement, power and design calculations are prospective scenarios, not guarantees. For replication requirement, their answer changes when the planned effect, variance, allocation, alpha, or attrition assumption changes.
How to interpret the replication requirement output
When interpreting replication requirement, report the design inputs as assumptions and compare at least one plausible alternative before committing resources to the plan.
As a second check for replication requirement, reversing the numerator and denominator answers a different question, so retain the direction printed in ceil((z+power-z)^2 × 2 × (SD/effect)^2).
A controlled sensitivity check for replication requirement
Change critical z while holding the remaining entries fixed, then state why the direction and size of the replication requirement change are plausible from ceil((z+power-z)^2 × 2 × (SD/effect)^2).
Repeat the replication requirement exercise with target effect. If a modest defensible change materially alters the interpretation, report both conditions rather than presenting that replication requirement scenario as exact.
Mistakes to avoid in the replication requirement setup
Before accepting replication requirement, compare every entered value with its label, unit, and allowed domain after reading the printed relationship from left to right.
For replication requirement, do not move a number between fields merely because the units look compatible; each label gives the number a different statistical role.
Another replication requirement failure occurs when a rounded output is reused as though it were the original measurement. Carry guard digits through calculations that depend on replication requirement, then round only the reported value.
What to record with replication requirement
Report replication requirement using ceil((z+power-z)^2 × 2 × (SD/effect)^2), followed by the entered values, units, exclusions, and analysis date. Name the replication requirement population or dataset boundary instead of leaving it implicit.
Keep the full calculator output with the record, including Required observations 63. A later replication requirement review can then distinguish a changed input from a different convention or software implementation.
Questions about replication requirement
What should be saved with replication requirement?
Save the entered values and units for critical z, power z, standard deviation, target effect, along with the analysis date, exclusions, software or formula version, and the relationship ceil((z+power-z)^2 × 2 × (SD/effect)^2). That record is sufficient to rebuild this specific replication requirement calculation.
Does replication requirement establish a causal or population conclusion?
No. The displayed replication requirement value is conditional on the entered data and named method. The replication requirement design, measurement process, and assumptions determine what can be concluded beyond those values.