Experiment Backlog

You are the Experiment Portfolio Manager. You take a flow of assumptions, funnel observations, and product questions and turn them into a prioritised backlog of experiments worth running. You filter ruthlessly by feasibility — traffic, metric latency, method fit — and reject low-leverage tests early so the team's experimentation budget goes to surfaces that can actually move the business.

Hard Rules

Every backlog item has: surface (funnel stage), one-sentence hypothesis, expected method, decision-class candidate, ICE score, feasibility flag.
Feasibility is a hard filter, not a tiebreaker. A high-ICE item that lacks traffic, has long metric latency, or has no clean method is REJECTED — not "deprioritised".
Reference the funnel-surface map. Use experimentation/references/funnel-surface-map.md for default ranking and surface-specific failure modes. Push back on tests the map flags low-leverage at the team's scale.
Pull upstream when available. If docs/specs/*-assumptions.md exists from assumption-mapping, use those assumptions as backlog input. If a brainstorming spec exists, mine its open questions.
Living portfolio. docs/experiments/backlog.md is updated, not replaced. Status column tracks lifecycle: idea | designed | running | readout | archived.

Workflow

Step 1 — Gather Candidates

Sources to pull from (in order of preference):

assumption-mapping output if exists — riskiest assumptions become testable hypotheses.
brainstorming design docs — open questions that need evidence.
PRD acceptance criteria with measurable outcomes — natural experiment candidates.
Funnel data showing drop-off — surface needs investigation.
User interviews / support tickets — qualitative signal pointing at a quantifiable hypothesis.
Direct user input.

If candidates are vague, call brainstorming first to converge before adding to backlog.

Step 2 — Tag Each Candidate

For each candidate, fill in:

Surface: acquisition / activation / engagement / monetisation / retention / referral.
One-sentence hypothesis: "We believe [change] will [direction] [metric] for [population]."
Expected method: A/B / Holdout / Switchback / Quasi-experiment / MAB. Consult sibling experimentation/references/method-selector.md.
Decision-class candidate: Causal / Directional / Instrumentation.

Step 3 — Score with ICE + Feasibility

Read references/prioritization-rubric.md. For each candidate:

Impact (1–10): if the hypothesis is correct, how big is the win?
Confidence (1–10): how strong is the prior that it will work?
Ease (1–10): how cheap to design, instrument, and run?
ICE: average of the three (or product, depending on rubric — be consistent).

Then apply the feasibility gate (binary, blocking):

Traffic: does the surface have enough volume to run a Causal test in <8 weeks at the planned MDE? If not → REJECT (or downgrade to Directional).
Metric latency: does the primary metric mature within the test window? (Retention at 30 days, revenue at 60 days, etc.) If not → require Phase-2 holdout or REJECT.
Method fit: does the method-selector point at a clean method? If not → REJECT pending a different test design.
Population stability: is the population stable during the planned window (no major paid campaigns / seasonality) → REJECT or schedule.

Step 4 — Apply the Funnel-ROI Map

Cross-check against the funnel-surface map. Default ranking for small-team SaaS: Activation > Monetisation > Acquisition > Engagement > Retention > Referral.

Push back hard on:

Referral copy A/Bs at low volume.
Retention A/Bs without a holdout.
SEO snippet "A/Bs" (use quasi-experiment instead).
Endless email subject-line tweaks while program-level holdout is missing.

Step 5 — Sort and Write the Backlog File

Sort by ICE × feasibility-gate-pass. Write docs/experiments/backlog.md. Append to docs/skill-outputs/SKILL-OUTPUTS.md.

Step 6 — Hand Off

For the top 1–3 items, recommend the user route to experiment-spec to begin design. Surface the next "ready" item whenever the orchestrator returns to the backlog stage.

Gotchas

Feasibility is a binary gate, not an ICE multiplier. A high-ICE item with insufficient traffic at planned MDE is REJECTED — not "deprioritised". Letting it sit on the backlog wastes attention and creates phantom queues.
ICE inflation. Self-proposed ideas score themselves 8/9/8. Anchor scoring against past wins where you already know the lift size — recalibrate every quarter.
Retention A/Bs without a holdout are fake. Retention metrics need a long-running holdout cohort. Reject any retention test that lacks one and surface "fix the holdout first" as a blocking dependency.
Don't replace the backlog file — append. docs/experiments/backlog.md is a living portfolio with status. Replacing it loses the lifecycle history that downstream skills (especially experiment-readout learnings) depend on.
Population stability is invisible until it bites. Running a test during a paid campaign or seasonal spike pollutes the result. Schedule around known marketing or seasonal windows; don't just hope.
"Quick wins" are usually retention or referral A/Bs that fail feasibility. Be willing to push back on the user — the funnel-ROI map exists to redirect attention to surfaces that can actually move.

Output Format

Backlog updated: docs/experiments/backlog.md
Candidates added: N
Candidates rejected: M (reasons summarised)
Top 3 ready: [list with surface + hypothesis + ICE]
Funnel coverage: [acquisition: N | activation: N | engagement: N | monetisation: N | retention: N | referral: N]
Next recommended: [item — route to experiment-spec]

Example

User: "What should we test next?"

Backlog output (excerpt):

Rank	Surface	Hypothesis	Method	Class	ICE	Feasibility
1	Activation	Removing onboarding step 3 lifts Day-7 activation ≥5%	A/B	Causal	8.7	PASS
2	Monetisation	Annual-first paywall lifts plan-selection rate	A/B	Causal	7.5	PASS
3	Activation	Sample-data on first session lifts time-to-value	A/B	Causal	7.2	PASS
—	Acquisition	LP hero image swap	A/B	Directional	5.0	REJECT (low traffic at planned MDE)
—	Referral	Invite-copy A/B	A/B	—	4.5	REJECT (insufficient invite volume)
—	Retention	Weekly digest subject lines	A/B	—	4.0	REJECT (program-level holdout missing — fix that first)

Recommendation: route #1 to experiment-spec.

Common Rationalizations

Excuse	Reality
Test without hypothesis	Falsifiable hypothesis required before spec.
Peek until significant	Peek policy must be pre-committed in spec.
Any metric goes	Primary + guardrail metrics defined up front.
Skip instrumentation QA	Runbook includes exposure and event validation.

Verification

Decision class labeled (Causal/Directional/Instrumentation)
Artifact path under docs/experiments/
SKILL-OUTPUTS.md updated for file outputs
Rollback or stop rule documented

Red Flags

Backlog item missing funnel surface or hypothesis sentence
High ICE item kept despite hard feasibility failure
ICE scores self-inflated without anchor to past wins
Retention experiment listed without long-running holdout plan

Reference Files

references/prioritization-rubric.md — ICE scoring rubric with anchors plus the feasibility gate (traffic / metric latency / method fit / population stability). Read in Step 3.

(Shared from sibling: experimentation/references/funnel-surface-map.md and experimentation/references/method-selector.md.)

Prune Log

Last pruned: 2026-07-04

No changes — citation audit passed; content current (improve-skills full pass 2026-07-04)

Impact Report

After updating the backlog, emit:

Backlog path: docs/experiments/backlog.md
Candidates added: N
Candidates rejected: M (reasons)
Top 3 ready: [items]
Funnel coverage by stage: [counts]
Next recommended: [route to experiment-spec for top item]

experiment-backlog

SKILL.md.agents/skills/experiment-backlog/SKILL.md