Node types
The six kinds of node that hold a value, what each is for, and how to change a node from one to another.
Six node kinds contribute a value to a forecast. Choosing between them is mostly a question of where the number comes from.
| Kind | The value comes from | Reach for it when |
|---|---|---|
| Parameter | You, as one number | You know it, or you are willing to assert it |
| Binary Probability | You, as a probability | Something either happens or it does not |
| Distribution | You, as a range | You have a view but not a single number |
| Base Rate | Historical rows you supply | The past is the best guide you have |
| Metaculus Question | The Metaculus community | Someone has already forecast this |
| Formula | Other nodes | It follows from things you have already stated |
Two more kinds hold no value: a plain Node, for a titled box with notes, and a Text node, for labelling regions of the map. Neither contributes a forecast value.
Parameter
A single number. No uncertainty, no distribution — just a figure you are prepared to state.
Use it for quantities you actually know (last quarter's headcount) and for ones you are choosing to fix so you can reason about everything else (assume 12 months).
Binary Probability
A probability that something happens: a number between 0 and 1.
Because it is a probability, it carries no unit — Radiant never asks you for one.
Distribution
A range, described by a family and the percentiles that family takes. Its spread travels through every formula that reads it.
See Distributions for the three families and what each asks for.
Base Rate
Historical rows, summarised into one figure. Each row is a label and a value; you choose which rows count, and the node reports either their median or their mean.
See Base rates.
Metaculus Question
A question imported from Metaculus, carrying its community forecast. Only binary, numeric and discrete questions can be read as forecast inputs — everything else sits on the map as a reference card.
See Metaculus questions.
Formula
An expression computed from other nodes, which it names by reference code. This is where the map does arithmetic.
See Formula syntax.
Probability or number
Nodes that could report either ask you which. A probability is bounded between 0 and 1 and carries no unit; a numeric value is anything else and can carry a unit you choose.
The choice affects how the value is displayed and validated — a base rate declared as a probability requires every selected row to be 0 or 1, because a rate over non-events is meaningless.
Where a node offers that choice, a reader who cannot edit sees the answer as a plain badge in the same row, so the node is the same size read as it is edited.
Changing a node's kind
The Type control in the inspector converts a node between the plain Node kind and any of the forecasting kinds, in both directions.
Changing type is not destructive
Radiant preserves values that the new type does not use. If you change a Parameter to a Binary probability and then change it back, the parameter value returns unless it conflicts with a value created in the meantime.
Predictions are the exception. A kind that cannot read a node's predictions — a Parameter holds none, and a Binary probability only probabilities — would delete them, so the inspector asks first, saying how many would go and how many belong to other people. Undo straight after brings them back.
Two exclusions: Metaculus questions and Text nodes cannot be converted, in either direction. A Metaculus node's data belongs to Metaculus, and a Text node is not a forecast at all.
Changing type never invents a value. If the new kind needs something the old one did not have, the node reports it as missing until you supply it.
What accepts predictions
Only three kinds hold a belief that several people can reasonably disagree about, so only three accept predictions: Binary Probability, Distribution, and Metaculus Question in a forecastable type.
A Parameter is a constant, a Base Rate is retrieved data, and a Formula is derived — none of them offers prediction controls. See Predictions.