diff --git a/source/components/StackedBarChart.tsx b/source/components/StackedBarChart.tsx
index a9578f480..2ec149853 100644
--- a/source/components/StackedBarChart.tsx
+++ b/source/components/StackedBarChart.tsx
@@ -3,7 +3,7 @@ import useDisplayOnIntersecting from 'Components/utils/useDisplayOnIntersecting'
 import React from 'react'
 import { animated, useSpring } from 'react-spring'
 import styled from 'styled-components'
-import { Rule } from 'Types/rule'
+import { EvaluatedRule } from 'Types/rule'
 import { capitalise0 } from '../utils'
 
 const BarStack = styled.div`
@@ -80,7 +80,7 @@ export function roundedPercentages(values: Array<number>) {
 }
 
 type StackedBarChartProps = {
-	data: Array<{ color?: string } & Rule>
+	data: Array<{ color?: string } & EvaluatedRule>
 }
 
 export default function StackedBarChart({ data }: StackedBarChartProps) {
diff --git a/source/components/TargetSelection.tsx b/source/components/TargetSelection.tsx
index ed7931aee..f23f5a09a 100644
--- a/source/components/TargetSelection.tsx
+++ b/source/components/TargetSelection.tsx
@@ -289,10 +289,10 @@ function AidesGlimpse() {
 	// Dans le cas où il n'y a qu'une seule aide à l'embauche qui s'applique, nous
 	// faisons un lien direct vers cette aide, plutôt qu'un lien vers la liste qui
 	// est une somme des aides qui sont toutes nulle sauf l'aide active.
-	const aidesNode = aides.explanation
-	const aidesDetail = aides.explanation.formule.explanation.explanation
-	const aidesNotNul = aidesDetail.filter(node => node.nodeValue !== 0)
-	const aideLink = aidesNotNul.length === 1 ? aidesNotNul[0] : aidesNode
+	const aidesNode = aides?.explanation
+	const aidesDetail = aides?.explanation.formule.explanation.explanation
+	const aidesNotNul = aidesDetail?.filter(node => node.nodeValue !== 0)
+	const aideLink = aidesNotNul?.length === 1 ? aidesNotNul[0] : aidesNode
 
 	if (!aides?.nodeValue) return null
 	return (
diff --git a/source/components/Value.tsx b/source/components/Value.tsx
index 6dd858c61..73ea25b36 100644
--- a/source/components/Value.tsx
+++ b/source/components/Value.tsx
@@ -2,7 +2,7 @@ import { T } from 'Components'
 import { formatValue, formatValueOptions } from 'Engine/format'
 import React from 'react'
 import { useTranslation } from 'react-i18next'
-import { Rule } from 'Types/rule'
+import { EvaluatedRule } from 'Types/rule'
 
 // let booleanTranslations = { true: '✅', false: '❌' }
 
@@ -18,7 +18,7 @@ let style = customStyle => `
 `
 
 export type ValueProps = Partial<
-	Pick<Rule, 'nodeValue' | 'unit'> &
+	Pick<EvaluatedRule, 'nodeValue' | 'unit'> &
 		Pick<
 			formatValueOptions,
 			'maximumFractionDigits' | 'minimumFractionDigits'
diff --git a/source/engine/traverse.ts b/source/engine/traverse.ts
index d0d7c3eac..8b9b3e290 100644
--- a/source/engine/traverse.ts
+++ b/source/engine/traverse.ts
@@ -1,7 +1,7 @@
 import { evaluateControls } from 'Engine/controls'
 import parseRule from 'Engine/parseRule'
 import { chain, path } from 'ramda'
-import { DottedName } from 'Types/rule'
+import { DottedName, EvaluatedRule } from 'Types/rule'
 import { evaluateNode } from './evaluation'
 import { parseReference } from './parseReference'
 import {
@@ -152,7 +152,7 @@ export let analyseMany = (
 			return parsedTarget
 		}),
 		targets = chain(pt => getTargets(pt, parsedRules), parsedTargets).map(
-			t =>
+			(t): EvaluatedRule =>
 				cache[t.dottedName] || // This check exists because it is not done in parseRuleRoot's eval, while it is in parseVariable. This should be merged : we should probably call parseVariable here : targetNames could be expressions (hence with filters) TODO
 				evaluateNode(cache, situationGate, parsedRules, t)
 		)
diff --git a/source/reducers/rootReducer.ts b/source/reducers/rootReducer.ts
index e0de4f39a..ad276a037 100644
--- a/source/reducers/rootReducer.ts
+++ b/source/reducers/rootReducer.ts
@@ -112,12 +112,25 @@ function conversationSteps(
 	return state
 }
 
-function updateSituation(situation, { fieldName, value, analysis }) {
-	const goals = analysis.targets
-		.map(target => target.explanation || target)
-		.filter(target => !!target.formule == !!target.question)
-		.map(({ dottedName }) => dottedName)
-	const removePreviousTarget = goals.includes(fieldName)
+function updateSituation(
+	situation,
+	{
+		fieldName,
+		value,
+		analysis
+	}: {
+		fieldName: DottedName
+		value: any
+		analysis: Analysis | Array<Analysis> | null
+	}
+) {
+	const goals =
+		analysis &&
+		(Array.isArray(analysis) ? analysis[0] : analysis).targets
+			.map(target => target.explanation || target)
+			.filter(target => !!target.formule == !!target.question)
+			.map(({ dottedName }) => dottedName)
+	const removePreviousTarget = goals?.includes(fieldName)
 		? omit(goals)
 		: identity
 	return { ...removePreviousTarget(situation), [fieldName]: value }
diff --git a/source/selectors/repartitionSelectors.ts b/source/selectors/repartitionSelectors.ts
index bcb1744ec..21c3dac00 100644
--- a/source/selectors/repartitionSelectors.ts
+++ b/source/selectors/repartitionSelectors.ts
@@ -25,7 +25,7 @@ import {
 	mergeCotisations
 } from './ficheDePaieSelectors'
 
-export type Cotisation = Rule & {
+export type Cotisation = Partial<Rule> & {
 	branche: Branch
 	montant: MontantPartagé
 }
diff --git a/source/types/rule.ts b/source/types/rule.ts
index 4c7f4ebef..7d8aa2fbd 100644
--- a/source/types/rule.ts
+++ b/source/types/rule.ts
@@ -3,9 +3,22 @@ export type DottedName = keyof typeof jsonRules
 
 export type Rule = {
 	dottedName: DottedName
-	nodeValue?: number
 	question?: string
+	unité: string
 	unit: string
 	name?: string
 	title?: string
+	defaultValue: any
+	icons: string
+	formule: any
+}
+
+// This type should be defined inline by the function evaluating the rule (and
+// probably infered as its return type). This is only a partial definition but
+// it type-checks.
+export type EvaluatedRule = Rule & {
+	nodeValue?: number
+	isApplicable: boolean
+	missingVariables: Array<DottedName>
+	explanation: EvaluatedRule
 }