Tasks / Metrics & Experimentation

Pick a North Star metric

Can the model pick the one metric that measures the value a product creates, and break it into inputs teams can move?

Task type v1.1 · 2 tasksLast changed 5 Oct 2026 · ChangelogDifficulty

What AI gets right here, and what you’ll still have to catch

From 16 graded outputs by 8 models. 75% were usable with at most a quick edit.

Reliably right

  1. Says how it could be gamed100% pass
    Identifies gaming vectors (tapping through, notification overuse, short-term spikes, revenue manipulation, MAU drift) and sets specific guardrails (quality completion, push caps, blocking metrics, cohort retention checks, subscriber churn tracking).
    Sonnet 5.5 · API · Revenue, actives, or something else?
  2. Sees the growth is narrow100% pass
    It shows the split (chains up, independents' filled shifts and fill rate down, more leaving) and tracks independent venues via segment reporting and guardrails.
    GPT-6 Luna · API · Growing, on paper
  3. Checks the North Star can be measured100% pass
    It flags the 64% confirmation gap and proposes instrumenting check-in/out, reconciliation, and auditing to fix it before the board readout.
    GPT-6 Luna · API · Growing, on paper

Where it slips

  1. Identifies material uncertainty55% pass
    It identifies the confirmation gap as an unknown but does not say how resolving it could change the North Star decision.
    GPT-6.1 Sol · API · Growing, on paper
  2. Addresses the actual decision58% pass
    The output commits to a North Star but does not state what result or condition would change that recommendation.
    GPT-6 Luna · API · Growing, on paper
  3. Avoids unsupported claims67% pass
    It presents 'easy to tap through' and 'we don't track today' as facts without support, and does not label them as assumptions.
    Opus 5.5 · Claude · Revenue, actives, or something else?

How it’s graded

Each check is built on how world-class product and growth leaders do this work, as they’ve described it on Lenny’s Podcast, and names the leader it comes from.

  1. Measures value created, not captured

    Does the chosen North Star measure the value customers get from the product, rather than revenue or a count of people who merely showed up?

    Passes when Picks a metric of value delivered to customers (a core action that predicts retention), and keeps revenue as a separate business measure.

  2. Breaks it into inputs teams can move

    Does the output break the North Star into a few input metrics, each one a team could own and move week to week, and pair it with a separate business measure of value captured?

    Passes when Gives a small tree of input metrics, each with an owner and a link to the North Star, plus the revenue or business measure it's paired with.

  3. Says how it could be gamed

    Does the output pressure-test the North Star for how teams could raise it without delivering more value, and set guardrail metrics against that?

    Passes when Names a realistic way the metric could be gamed in this product and the guardrails that would catch it.

Plus our standard checks

Uses the supplied evidence correctly · Addresses the actual decision · Respects explicit constraints · Identifies material uncertainty · Avoids unsupported claims · Produces the required deliverable · Gets the base of every number right · and 1 written for each task, which you’ll see in the tasks below.

The tasks

Read the brief, then compare up to three outputs, each with the LLM judge’s verdict on every check. Highlights mark what a PM had to fix.

The brief

You're the Head of Product at Simmer. Our CEO wants MRR as the company's North Star metric; our growth lead wants monthly active users. Write a recommendation for both of them, in no more than 700 words: the North Star you'd pick and why, three or four input metrics teams could own, and the guardrails that stop it being gamed. What we know is below.

What the model was given5 items: About Simmer, What people do, Retention (12 months of cohorts), Subscriptions, Last year's notification test
About SimmerA recipe and meal-planning app. Free to use; Simmer Plus ($6 a month) unlocks meal plans and Cook Mode's step-by-step timers for every recipe. 2.1M monthly active users, 140,000 paying subscribers, MRR of $840,000.
What people doSave a recipe (savers save 4 a week on average). Cook a recipe in Cook Mode, logged when someone reaches the last step. Plan a week of meals (7% of monthly actives have ever done it). 68% of monthly actives only browse: they arrive from search, read one recipe and leave.
Retention (12 months of cohorts)Users who cook two or more recipes in Cook Mode in a week: 61% still active at month 6. Weekly planners: 54%. Users who save recipes but never cook one in Cook Mode: 9%. Browse-only users: 4%.
Subscriptions82% of new subscribers had cooked at least three recipes in Cook Mode in their first two weeks.
Last year's notification testA daily 'recipe of the day' push notification raised monthly active users by 6%. Uninstalls doubled over the same period, and Cook Mode completions didn't change.
What a strong answer doesThe answer key the graders mark against

Recommends a North Star built on cooking, such as weekly cooks (people who complete two or more recipes in Cook Mode in a week) or recipes cooked per week, because cooking is the value moment and it predicts both retention (61% at month 6) and subscribing (82% of new subscribers cooked first). Rejects MRR as the North Star because it measures value captured, and lags (keep it as the business measure the North Star is paired with). Rejects monthly actives because 68% of them only browse (4% retention) and the push test shows it can be inflated while the product gets worse. Gives input metrics a team could own, such as first cook within a week of signing up, cooks per active cook, and share of savers who cook what they saved, and guardrails such as uninstalls and notification opt-outs, and subscriber retention.

Critical failures (cap the score at 40)
  • Recommends MRR or monthly active users as the North Star
Task

Mid-level · v1.0

The outputs

8 setups answered this brief.

Usable with a quick edit11 of 11 checks passed

The output is well-structured, uses evidence correctly, and covers all required elements; a PM could use it with only minor wording tweaks, without re-checking evidence or redoing reasoning.

Output

To: CEO, Growth Lead From: Head of Product Re: Simmer's North Star

Recommendation

Make the North Star Weekly Active Cookers (WAC): users who complete Cook Mode on two or more recipes in a week.

Both of your metrics matter, but neither measures the thing that drives the business.

Why not MAU. 68% of our 2.1M monthly actives arrive from search, read one recipe and leave. They retain at 4% at month 6. Last year's push test shows the risk: MAU rose 6%, uninstalls doubled, and Cook Mode completions didn't move. A MAU target rewards exactly that trade.

Why not MRR. MRR ($840K, from 140K subscribers at $6) is the outcome we want, but it lags. It can also be moved by a price change or a paywall tweak without making the product better, and it tells a team nothing about what to do this week.

Why WAC. People who cook twice or more a week retain at 61% at month 6, against 9% for savers who never cook and 4% for browsers. And 82% of new subscribers cooked at least three recipes in Cook Mode in their first two weeks. Cooking sits upstream of both retention and revenue, so growing WAC should grow MRR, and teams can influence it within a sprint.

MRR stays as our top-line business outcome, reported alongside WAC. MAU becomes a funnel-health metric, since it is the pool WAC is converted from.

One caveat: these are correlations, and committed cooks may simply be our best users anyway. In the first quarter we should run a holdout experiment, such as a stronger first-week cooking prompt, to confirm that causing more cooking causes better retention and conversion.

Input metrics teams can own

  1. New-user activation (Onboarding): % of new users who complete a Cook Mode recipe within 7 days, with the 3-recipes-in-14-days rate tracked as the subscription-intent signal.
  2. Save-to-cook rate (Discovery and Cook Mode): % of savers who cook a saved recipe in Cook Mode within 14 days. Savers who never cook retain at 9%, so this is our biggest leak.
  3. Browse-to-return conversion (Growth and SEO): % of search-landing visitors who save a recipe or come back within 7 days. This gives Growth a real lever on the 68%, and on MAU quality.
  4. Planning adoption (Planning): % of monthly actives who build a weekly plan. Only 7% have ever done it, yet weekly planners retain at 54%.

Guardrails against gaming

Against cheap cooking events. Completion is logged when someone reaches the last step, so tapping through counts. - Track a "quality completion" (minimum elapsed time relative to recipe length, or timer use) and report WAC on that basis. - Monitor median time per completion for sudden drops. - Add an occasional "Did you cook it?" prompt to calibrate against self-report.

Against the notification trap. - Set a hard cap on push frequency. - Treat uninstall rate and notification opt-outs as blocking metrics: any experiment that worsens either is not shipped, whatever it does to WAC or MAU.

Against short-term lifts. - Judge any WAC gain by its 30- and 90-day cohort retention, so we don't buy a spike with users who disappear.

Against revenue gaming. - Track subscriber churn, refund rate and cancellation-flow completion alongside MRR. - Don't count MRR gains from price changes or paywall aggressiveness as product wins. - Don't gate Cook Mode so tightly that new users can't reach the 3-recipe habit that predicts subscribing.

Against MAU drift. - Keep reporting MAU, but as a watch metric with no team target. If MAU rises while WAC is flat, we treat it as a warning sign rather than a win.

What each of you gets

  • CEO: a metric that leads MRR and that teams can act on, with MRR still reported at the top. If WAC grows and conversion holds, MRR follows.
  • Growth lead: ownership of the biggest untapped pool, the browse-only majority. Success is measured by how many of them become cookers, not by how many we can get to open the app.

I'd propose we adopt WAC from next quarter, baseline it in the first month, set targets once we see the quality-adjusted number, and review the causal experiment results at the end of the quarter.

Grades and run details

Decision model 95 · LLM judge 100
Decision model checks
  • passUses the supplied evidence correctly57%
  • passAddresses the actual decision93%
  • passRespects explicit constraints46%
  • passIdentifies material uncertainty75%
  • partialAvoids unsupported claims24%
  • passProduces the required deliverable94%
  • passAnswers both proposals with the data100%
  • passMeasures value created, not captured100%
  • passGets the base of every number right78%
  • passBreaks it into inputs teams can move100%
  • passSays how it could be gamed100%
Run
Run
#1
API response time
22 s
Submitted
5 Oct 2026

Needs more than a quick edit9 of 11 checks passed

The output incorrectly claims the baseline isn't tracked, which a PM would need to correct before using it. The unsupported 'easy to tap through' assertion also needs verification.

Output

Simmer's North Star: Weekly Active Cooks

To: [CEO], [Growth Lead] From: Head of Product

Recommendation

Our North Star should be Weekly Active Cooks: users who complete two or more recipes in Cook Mode in a given week.

Neither MRR nor MAU is wrong as something to watch. But neither works well as the one number every team steers by. Weekly Active Cooks sits between them. It is the behaviour that best predicts both retention and revenue, and teams can move it week to week.

Why not MRR

MRR is the outcome we're ultimately accountable for, and it stays on the board. As a North Star, it has two problems.

  • It lags. Revenue moves after behaviour has already changed, so teams learn too late whether their work helped.
  • Most teams can't touch it directly. The levers that move MRR fastest are pricing, paywalls and discounting. Those can lift revenue in the short term while hurting the habit that sustains it.

The behaviour that comes before revenue is cooking. 82% of new subscribers cooked at least three recipes in Cook Mode in their first two weeks.

Why not MAU

MAU measures reach, and reach matters. But our own data shows it rewards the wrong things.

  • Most of it doesn't stick. 68% of monthly actives only browse: they arrive from search, read one recipe and leave. Only 4% of them are still active at month 6.
  • It's easy to inflate. Last year's daily push notification raised MAU by 6%. Uninstalls doubled, and Cook Mode completions didn't change. MAU went up while the business got slightly worse.

Why Weekly Active Cooks

  • It predicts retention. 61% of users who cook twice a week are still active at month 6. That is the strongest retention signal we have, ahead of weekly planners (54%), savers who never cook (9%) and browse-only users (4%).
  • It predicts revenue. Cooking comes before subscribing for most new subscribers.
  • It reflects real value. Someone who cooked dinner with Simmer got what we promise.
  • It's weekly. Teams get feedback fast enough to iterate.

A caveat: this evidence is correlational. People who cook may simply be more committed to begin with. Before we fully commit, I propose a holdout test of one cook-encouraging change to confirm that causing cooking improves retention. We also need to establish the current baseline, which we don't track today.

Input metrics teams can own

  1. Browse-to-cook conversion (owner: Growth/SEO). The share of search visitors who start Cook Mode in that visit or return within seven days. Our biggest pool of users is the 68% who browse, and this turns reach into habit. It also gives the growth team a version of the audience goal that counts.
  2. New-user activation (owner: Onboarding). The share of new users who cook three recipes in their first 14 days. This mirrors the path most subscribers took.
  3. Save-to-cook rate (owner: Recipe/Discovery). The share of saved recipes cooked within 14 days. Savers save four recipes a week, but saving alone retains only 9% of them. Reminders, shopping lists and "cook what you saved" features should close this gap.
  4. Weekly planning adoption (owner: Meal Planning). The share of actives who plan a week of meals. Only 7% have ever done it, yet planners retain at 54%. Planning is also a Plus feature, so it has a direct line to revenue.

Guardrails

  • MRR and free-to-paid conversion, reviewed monthly. If Weekly Active Cooks rises but conversion falls, we may be giving away too much free.
  • Uninstall rate and notification opt-outs. Any engagement push that worsens these gets reviewed, given what happened with the daily notification.
  • Cook Mode completion quality. We currently log a cook when someone reaches the last step, which is easy to tap through. We should only count completions with plausible time spent on the steps. A share of completions should also show supporting signals, such as timers used or the recipe rated or repeated.
  • Six-month retention by cohort. This is the ultimate check that more cooks means more lasting users.
  • MAU, tracked but not targeted. If reach collapses, the funnel feeding Weekly Active Cooks dries up.

Next steps

If you both agree, we will:

  • instrument the metric and the quality filter,
  • publish a baseline within three weeks,
  • run the causal test, and
  • set first-half targets for each input metric with their owning teams.

Claims the judge couldn’t find in the brief

  • We currently log a cook when someone reaches the last step, which is easy to tap through.
  • We also need to establish the current baseline, which we don't track today.

Grades and run details

Decision model 100 · LLM judge 75
Decision model checks
  • passUses the supplied evidence correctly59%
  • passAddresses the actual decision81%
  • passRespects explicit constraints45%
  • passIdentifies material uncertainty77%
  • passAvoids unsupported claims26%
  • passProduces the required deliverable82%
  • passAnswers both proposals with the data99%
  • passMeasures value created, not captured100%
  • passGets the base of every number right65%
  • passBreaks it into inputs teams can move100%
  • passSays how it could be gamed99%
Run
Run
#1
Time to output
23 s
Submitted
5 Oct 2026

Usable with a quick edit11 of 11 checks passed

The output is clear, evidence-based, and covers all required elements; a PM could act on it with minimal editing.

Output

Recommendation: optimize for weekly cooking, not revenue or visits

Our North Star should be Weekly Engaged Cooks: the number of unique users who complete at least two recipe-cooking sessions in Cook Mode within a rolling seven-day period. Count each person once, across free and paid users.

Simmer’s core promise is helping people make meals—not merely find recipes. This metric captures users repeatedly receiving that value.

The evidence points toward cooking: - Users cooking at least twice a week have 61% month-six retention, versus 9% for save-only users and 4% for browse-only users. - 82% of new subscribers cooked at least three recipes in their first two weeks. - Weekly planners also retain well, at 54%, but planning has reached only a small minority of users. It should support cooking, not define value for everyone.

These are associations, not proof that pushing users across a threshold causes retention or subscription. They are nevertheless our strongest starting evidence; we should test whether product changes that increase genuine cooking also improve those outcomes.

Why not MRR or MAU?

To our CEO: MRR remains a critical business outcome. But as the North Star, it could reward price increases or aggressive paywalls even while fewer people get value. Weekly cooking gives teams a customer-value objective with a plausible connection to durable revenue.

To our growth lead: MAU measures reach, but treats a one-recipe search visitor like a habitual cook. Our notification experiment demonstrates the danger: MAU rose 6%, uninstalls doubled, and cooking completions stayed flat. That was more activity, not more value.

Four input metrics teams can own

OwnerInput metricPurpose
Acquisition and discoveryFirst-cook activation: percentage of new users completing a Cook Mode session within seven daysTurn search traffic and browsing into useful cooking experiences; segment by acquisition source.
Onboarding and recipe experienceSecond-cook conversion: percentage of first-time cooks completing another session within the next seven daysBuild repeat value rather than celebrate a single trial.
Retention and meal planningWeekly engaged-cook retention: percentage of Engaged Cooks who qualify again the following weekGrow a durable habit; test planning and saved-recipe resurfacing as mechanisms.
Cook ModeSuccessful-session rate: percentage of genuine Cook Mode starts that reach completionRemove usability and reliability barriers during cooking.

These are drivers, not independent targets to maximize at any cost. Track their absolute user counts alongside rates so teams cannot improve percentages simply by shrinking eligibility.

Guardrails against gaming

1. Measure cooking, not button presses. Reaching the last step is a proxy, not proof of a cooked meal. Exclude automated activity and duplicate completion events. Audit suspicious completion patterns and periodically validate the proxy through user research. Don’t reward tapping through steps, auto-completion, or cosmetic changes to logging.

2. Protect the whole experience. Monitor uninstalls, notification opt-outs, complaints, and cooking satisfaction. Reject “growth” that increases qualifying activity through nagging while materially worsening these measures. Preserve browse-only usefulness; not every visitor needs to become a tracked cook.

3. Require durable gains. Evaluate experiments on sustained weekly cooking and cohort retention, not just a short-lived threshold crossing. Keep metric definitions stable and report results separately for new, existing, free, and paid users.

4. Keep economics visible. Review MRR, paid conversion, subscriber churn, and contribution margin alongside the North Star. More cooking is not enough if it undermines a sustainable business.

Bottom line: MAU tells us who arrived; MRR tells us what we earned. Weekly Engaged Cooks tells us whether Simmer is becoming useful enough to return to—and pay for.

Grades and run details

Decision model 95 · LLM judge 100
Decision model checks
  • passUses the supplied evidence correctly77%
  • passAddresses the actual decision64%
  • passRespects explicit constraints59%
  • partialIdentifies material uncertainty58%
  • passAvoids unsupported claims60%
  • passProduces the required deliverable96%
  • passAnswers both proposals with the data64%
  • passMeasures value created, not captured100%
  • passGets the base of every number right86%
  • passBreaks it into inputs teams can move100%
  • passSays how it could be gamed100%
Run
Run
#1
API response time
28 s
Submitted
5 Oct 2026

Check by check

Where the outputs differ comes first. Open a check to read the judge’s reasons. “Mixed” means the two graders disagreed.

Where they differ 2

Uses the supplied evidence correctlyRightMixedRight
Sonnet 5.5 · API

All statements about the current situation are taken directly from the supplied context, with no invented facts.

Opus 5.5 · Claude

The output claims the baseline isn't tracked and that tapping through is easy, neither of which appears in the supplied context or follows from it.

GPT-6.1 Sol · API

All factual claims about the current situation are directly from the supplied context.

Avoids unsupported claimsRightMixedRight
Sonnet 5.5 · API

Forecasts and causal claims are labelled as such (e.g., 'should grow', 'caveat: these are correlations'), and no interpretation is presented as established fact.

Opus 5.5 · Claude

It presents 'easy to tap through' and 'we don't track today' as facts without support, and does not label them as assumptions.

GPT-6.1 Sol · API

Causal claims are clearly labelled as associations to be tested, and no interpretations are presented as established fact.

All got right 9

Addresses the actual decisionRightRightRight
Sonnet 5.5 · API

Commits unambiguously to Weekly Active Cookers as the North Star, addresses both the CEO and Growth Lead, and states that a holdout experiment would confirm causality and could change the call.

Opus 5.5 · Claude

It commits early to Weekly Active Cooks as the North Star, framed for the CEO and Growth Lead, and says a causal holdout test would confirm the choice.

GPT-6.1 Sol · API

Commits unambiguously to Weekly Engaged Cooks as North Star, addresses both CEO and growth lead, and indicates that testing the causal link could change the call.

Respects explicit constraintsRightRightRight
Sonnet 5.5 · API

The output is a memo to the CEO and Growth Lead, stays under 700 words, and respects the requested form and reader.

Opus 5.5 · Claude

The output is a recommendation under 700 words, addressed to the CEO and Growth Lead, and includes input metrics and guardrails as requested.

GPT-6.1 Sol · API

The output is a recommendation under 700 words, addresses the named readers, and includes the requested input metrics and guardrails.

Identifies material uncertaintyRightRightRight
Sonnet 5.5 · API

Explicitly names the correlation-vs-causation uncertainty and proposes a holdout experiment to resolve it, with the result potentially changing the decision.

Opus 5.5 · Claude

It names the correlational nature of the evidence and proposes a holdout test to resolve causality, and notes the need to establish the baseline.

GPT-6.1 Sol · API

Acknowledges the evidence is associative, not proof of causation, and says testing product changes that increase cooking will resolve whether it improves retention and subscription.

Produces the required deliverableRightRightRight
Sonnet 5.5 · API

The memo is complete, within the word limit, and directly usable by the CEO and Growth Lead with at most light edits.

Opus 5.5 · Claude

The memo is complete, within the word limit, and usable by the CEO and Growth Lead with light edits.

GPT-6.1 Sol · API

Provides a complete recommendation with North Star, input metrics, and guardrails, usable by the CEO and growth lead with at most light edits.

Answers both proposals with the dataRightRightRight
Sonnet 5.5 · API

Uses the data to reject MAU (68% browse, 4% retention, push test inflated MAU while uninstalls doubled) and MRR (lags, can be moved by price/paywall without product improvement).

Opus 5.5 · Claude

It uses the data to reject MRR (lags, teams can't touch it, cooking precedes subscribing) and MAU (68% browse, 4% retention, push test inflated MAU while uninstalls doubled).

GPT-6.1 Sol · API

Uses the push-test data to reject MAU and argues MRR could reward value-destroying moves; both are clearly rejected with data.

Measures value created, not capturedRightRightRight
Sonnet 5.5 · API

The North Star (Weekly Active Cookers) measures value delivered (cooking), and MRR is kept as a separate business outcome.

Opus 5.5 · Claude

Weekly Active Cooks measures value delivered (cooking), and MRR is kept as a separate business measure.

GPT-6.1 Sol · API

The North Star measures cooking, a core value action that predicts retention, and keeps MRR as a separate business measure.

Gets the base of every number rightRightRightRight
Sonnet 5.5 · API

All percentages are quoted directly from the supplied context; no derived figures require a base check.

Opus 5.5 · Claude

All percentages and rates are taken correctly from the supplied data, and no derived figures are miscalculated.

GPT-6.1 Sol · API

All percentages and rates are taken correctly from the context, and input metrics define their denominators clearly.

Breaks it into inputs teams can moveRightRightRight
Sonnet 5.5 · API

Provides four input metrics (new-user activation, save-to-cook rate, browse-to-return conversion, planning adoption) each with an owner, and pairs WAC with MRR as the business measure.

Opus 5.5 · Claude

It breaks the North Star into four input metrics (browse-to-cook conversion, new-user activation, save-to-cook rate, weekly planning adoption) each with an owner and link to the North Star, and pairs it with MRR.

GPT-6.1 Sol · API

Four input metrics are assigned to specific teams and linked to the North Star, with MRR and other business metrics kept alongside.

Says how it could be gamedRightRightRight
Sonnet 5.5 · API

Identifies gaming vectors (tapping through, notification overuse, short-term spikes, revenue manipulation, MAU drift) and sets specific guardrails (quality completion, push caps, blocking metrics, cohort retention checks, subscriber churn tracking).

Opus 5.5 · Claude

It identifies that completions could be gamed by tapping through without cooking, and proposes guardrails like plausible time spent and supporting signals.

GPT-6.1 Sol · API

Identifies tapping through steps, auto-completion, and nagging as gaming risks, and sets guardrails like uninstalls, opt-outs, and satisfaction monitoring.

Results

Every setup we’ve tested on this task type, across all its tasks and repeats, graded on the current checklist. Calibrated.

#Model · HarnessTask scoreDecision modelLLM judgeRunsCritical failures
1Sonnet 5.5withAPI95.996.72None
2GPT-6.1 SolwithAPI97.793.32None
3GPT-6 LunawithAPI95.588.32None
4GPT-6 AstrawithChatGPT94.288.32None
5Opus 5.5withClaude94.680.82None
6Haiku 5.5withAPI88.881.72None
7Gemini 3.8 FlashwithAPI78.965.82None
8Gemini 3.5 Flash-LitewithGemini54.438.321 capped

What you get for the cost

GPT-6 Luna · API scores within 4 points of Sonnet 5.5 · API at about a twentieth of the cost.

Task score against relative cost for each setup. The table below has the same figures.304050607080901001×3×10×30×Cost per output, relative to the cheapest setup (log scale) →↑ Task scoreSonnet 5.5 · API: task score 96, 22× the cheapestGPT-6.1 Sol · API: task score 96, 9.6× the cheapestGPT-6 Luna · API: task score 92, the cheapestGPT-6 Astra · ChatGPT: task score 91, 52× the cheapestOpus 5.5 · Claude: task score 86, 36× the cheapestHaiku 5.5 · API: task score 86, the cheapestGemini 3.8 Flash · API: task score 71, 7.5× the cheapestGemini 3.5 Flash-Lite · Gemini: task score 44, 1.8× the cheapest, 1 critical failureSonnet 5.5 · APIGPT-6.1 Sol · APIGPT-6 Luna · APIGPT-6 Astra · ChatGPTOpus 5.5 · ClaudeHaiku 5.5 · APIGemini 3.8 Flash · APIGemini 3.5 Flash-Lite · Gemini
Best valueNobody beats these on both score and costAt least one critical failure
Task score and relative cost by setup
SetupTask scoreRelative cost (cheapest = 1)
GPT-6 Luna · API921.0×
Haiku 5.5 · API861.1×
Gemini 3.5 Flash-Lite · Gemini441.8×
Gemini 3.8 Flash · API717.5×
GPT-6.1 Sol · API969.6×
Sonnet 5.5 · API9622×
Opus 5.5 · Claude8636×
GPT-6 Astra · ChatGPT9152×

Cost is each output’s tokens at the model’s list price, shown relative to the cheapest setup. Runs done in an app have no usage meter, so theirs are estimated from the same setup’s measured runs. How we compare cost

About the task

The PM job

Choosing the metric the whole company steers by.

Why it matters

Pick revenue and you steer by the rear-view mirror. Pick a vanity metric and teams will happily grow it while the product gets worse.

What good looks like

  • Measures value delivered to customers, not value captured
  • Grounded in what predicts retention in the data
  • Broken into input metrics a team can own
  • Says how it could be gamed, with guardrails

Deliberately not measured

  • Dashboard design
  • Naming
Capability tested

Metric design

The failure we’re looking for

Revenue, or a vanity metric, as the North Star

Grading

Decision model and LLM judge, calibrated against a blind PM review