One formula, in plain sight.
The illustrative index is a weighted average of the dimension scores that are actually available. That’s all it is. Here is every rule, with live examples you can change.
The formula
In words: multiply each available dimension’s score by its weight, add those up, and divide by the total weight of the dimensions you used. Dimensions without recent data aren’t in the sum or the divisor, so they can’t drag the index down.
The rules, in order
Choose a period
A period is the last 7, 30 or 90 days ending on a date. In this demo the synthetic record runs from 1 July to 28 September 2026.
Decide which dimensions are configured
Every dimension with a weight above zero is configured. By default, all six are, each with a weight of 1. Setting a weight to 0 removes that dimension from both the index and the coverage count.
Check availability and freshness
A configured dimension is available if its most recent observation is no older than the freshness window (21 days by default), measured from the end of the period. If it has never been recorded it is missing; if its latest record is too old it is stale. Both are excluded and labelled.
Score each available dimension
Its score is the mean of the daily sample scores dated inside the period. If there are none inside the period but the latest is still within the freshness window, that latest score is carried forward, and labelled as such.
Combine
Index = Σ(weight × score) ÷ Σ(weight), over available dimensions only. If no dimension is available the result is Insufficient data, never zero.
Show coverage separately
Coverage = available ÷ configured dimensions. It sits beside the index, never folded into it. A low-coverage index is still the average of what’s there; coverage tells you how much is there.
Weights, live
Change a weight and every contribution updates. Effective weight is a dimension’s share of the total weight in use; contribution is how many index points it supplies.
Missing is not zero
The most important rule. A tool that treats a missing dimension as a score of zero will show a falling number whenever data stops arriving, implying something got worse when nothing was measured at all.
If every configured dimension is missing or stale, Vital shows Insufficient data in place of a number. Try it in the calculator above: set the only available weights to zero.
Staleness
Every source has a recency label. The freshness window decides how old a dimension’s latest record may be before it stops counting. It’s a published, adjustable demo setting, not a hidden penalty that quietly lowers scores.
| Dimension | Latest record | Age | Status |
|---|
Scenarios stay separate
A what-if lets you type a hypothetical score for a dimension and see the arithmetic. It is stored as a hypothetical input and never overwrites a recorded observation. It is not a prediction of what would happen if you changed anything in your life.
Definition & version
The method is versioned. Any change to weights, rules or windows would ship as a new version, and every summary records which version produced it.