Support & How It Works

Self-service help: how to use it, the math (with sources), safe usage, and managing your Pro subscription. Support is provided through these docs, we don't offer one-to-one support.

How support works: This page (plus the in-app Method docs) is the support, there's no guaranteed one-to-one help, which keeps the tool affordable. Found a problem? Use the bug report form. Manage billing, cancel, or get a refund anytime via Lemon Squeezy My Orders, enter the email you used at purchase and Lemon Squeezy emails you a secure sign-in link (no account to create).
Getting started Understanding results The math (with sources) Safe & private use Pro & licenses Report a bug Cancel / billing Troubleshooting

Getting started

What is this, in one sentence?

A free, educational learning tool for exploring hypothetical investment scenarios, so you can see how different choices might play out and walk into a financial professional's office prepared. It is not advice and never recommends a specific security.

How do I use it? (the basic flow)
  • Scenario Lab, sketch a scenario: a starting amount, what you add each year, your horizon, inflation, and a goal (use round, made-up numbers). Pick an approach from conservative to aggressive. Everything updates live.
  • Scenario Snapshot, see the hypothetical results in one place: the median, the unlucky-to-lucky range, the share of simulations reaching the goal, allocation, and where each piece is commonly placed for taxes.
  • Scenario Method, every formula is disclosed, with adjustable "influence levers" (fees, taxes, behavior, crash chance, mean reversion).
  • Self-check, runs the full validation test suite in your browser, on load.
Do I have to enter real numbers?

No, please don't. Use a fake name and round, hypothetical figures. You get the exact same insight, and there's nothing personal to protect. The goal is to learn the dynamics, not to record your finances.

How do I save or share a scenario?

On Scenario Snapshot, use Export (CSV scenario snapshots) or Print Report (a polished PDF). Use Share this scenario to send a file someone can open in any browser. Your data lives only in your browser, so exporting is how you keep a copy.

Understanding the results

What is the "median," and the 10th/90th range?

We play your whole horizon out 2,000 times, each a different random sequence of good and bad years, then sort the endings. The median is the middle outcome (half do better, half worse). The 10th percentile is an unlucky 1-in-10 result; the 90th is a lucky 1-in-10. Most futures land in between. It's a range of possibilities, not a prediction.

Why isn't there just one number?

Because markets are uncertain. A single number hides the risk. Showing the range, including the bad years, is the honest way to plan. See "the math" below for how the simulation works.

Are these projections a prediction of the market?

No. They are hypothetical illustrations of the assumptions you enter. Different assumptions produce different results, and your actual results will differ, possibly a lot. The tool can't and doesn't predict markets.

The math behind it, with sources

These are reputable, independent references for the concepts the tool uses. They are not the source of our specific figures, which are illustrative and dated, verify current data before relying on any number. Full internal write-up is in the app's Method tab and docs/METHODOLOGY.md.
Monte Carlo simulation

Instead of one smooth average, we simulate thousands of randomized multi-year paths to map the range of outcomes. Standard technique in finance, engineering, and science.

Volatility, correlation & diversification

Risk is the year-to-year swing (standard deviation), computed with the full correlation matrix, because assets move partly together, the honest risk is higher than a naive average. This is the core of modern portfolio theory.

Sequence-of-returns risk

The order of good and bad years matters enormously once you're withdrawing, early losses do lasting damage. We illustrate this directly.

Valuation & forward returns (CAPE)

Today's US large-cap valuations are historically high (CAPE ~40), and high starting valuations have historically preceded lower long-run returns, which is why our default forward assumptions mark US returns down.

Mean reversion

Deep crashes have historically been followed by recoveries over long horizons. A mild mean-reversion setting keeps very long projections from being unrealistically gloomy.

Inflation & real returns

What matters is purchasing power. We convert future dollars to "today's dollars" by removing inflation, so the headline reflects real buying power.

Withdrawals & the 4% / Trinity study

Decades of research examine how much a mix can sustainably support in withdrawals. We model depletion risk rather than asserting one "safe" rate.

Tax placement (where each piece is commonly placed)

Assets that throw off heavily-taxed income are commonly held where tax is deferred or free, which can improve after-tax results. General educational context, not personalized tax advice.

The behavior gap & dollar-cost averaging

Investors often underperform their own funds by buying high and selling low; our "behavioral drag" lever reflects that. Phasing money in reduces timing risk (not expected return).

Further reading / sources

Using it safely & privately

Where does my data go?

We don't store your scenarios. Your figures stay in your browser on your device (local storage) and are never sent to or saved by us. To keep a copy, Export/Print it; to erase it, clear your browser or use the Delete all my data button on Scenario Snapshot.

How does it handle my data?

It's an ordinary web page on your own device, not a secure, login-protected vault, so please use hypothetical, rounded numbers and avoid real names or personal data. The app itself doesn't send the figures you type anywhere; they stay in your browser. Our host and analytics provider(s) may use cookies to measure usage and improve the product (you can block cookies in your browser), but we don't intentionally collect your scenario inputs. We don't control your device's security, so on a shared computer keep inputs hypothetical or use a private/incognito window.

Should I use it on a public or shared computer?

Keep your inputs hypothetical there. We don't manage the security of your device, and the tool isn't password-protected, it's a sandbox. On a shared machine, use made-up numbers, a private/incognito window (which saves nothing), or clear the browser when you're done.

What about analytics & cookies?

Our website host and analytics provider(s) may use cookies and similar technologies to measure how the product is used and to run A/B tests, so we can improve it. This is standard usage measurement, we don't use it to collect the figures you enter, and we don't run advertising trackers. You can block or delete cookies in your browser settings at any time. See the Privacy Policy.

Pro & licenses

What's the difference between Free and Pro?

Free includes the full planner, simulation, charts, and one saved scenario. Pro unlocks unlimited saved scenarios so you can compare many what-ifs side by side, plus every update we release while you're subscribed.

How is Pro billed?

Pro is an annual subscription that renews each year until you cancel. Cancel anytime from Lemon Squeezy My Orders (enter your purchase email), you'll keep Pro access through the end of the period you already paid for, and you won't be charged again. No refunds, including for partial periods.

How do I activate Pro?

After you subscribe you receive a license key. In the app, click "+ New scenario" → Activate, paste your key, and unlimited scenarios unlock on that browser. Keep your key private, don't share or publish it. Your key stays valid while your subscription is active.

How do I cancel?

Go to Lemon Squeezy My Orders, enter the email you used at purchase to get a secure sign-in link, then choose Manage Subscription → Cancel. Canceling stops future renewals; you keep access until your paid period ends.

How does support work?

Support is self-service through this help page and the in-app Method documentation, there's no guaranteed one-to-one support. This keeps the product affordable. For billing or cancellation, use Lemon Squeezy My Orders; for anything else, email scenario_lab@julieclarkson.com (best-effort; response times vary).

Report a bug

Something not working? Send the details and we'll use them to fix it. (This goes to our queue, it isn't a live chat, and we can't promise an individual reply.)

Cancel or manage your subscription

Pro is an annual subscription. You can cancel anytime through Lemon Squeezy, you'll keep access through the end of your paid period.

Billing, payment method, invoices, cancellation, and refund requests are all handled securely through Lemon Squeezy My Orders. There is no separate account to create, go to My Orders, enter the email you used at purchase, and Lemon Squeezy emails you a secure sign-in link.

Mind sharing why you're canceling? (optional, it helps us improve)

Open My Orders to cancel → Update billing / download a receipt

Refunds are reviewed through Lemon Squeezy My Orders. If something genuinely didn't work for you, request a refund there, we aim to be fair.

Troubleshooting

My scenarios disappeared

Scenarios are saved in your browser's local storage. They're cleared if you clear your browsing data, use a private/incognito window, or switch browsers/devices. Use Export to keep a copy.

My license key won't activate

Check for extra spaces, confirm the key is the one emailed at purchase, and make sure you're online (activation needs a quick license check). If it still fails, use the bug report form with your order details, or check Lemon Squeezy My Orders.

The page looks broken or old after an update

Do a hard refresh (Cmd/Ctrl+Shift+R) to load the latest version.

I have another question

Support is self-service through these docs and the in-app Method pages, we don't offer one-to-one support. For a problem, use the bug report form; for billing or cancellation, use Lemon Squeezy My Orders.

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Investment Scenario Lab is an educational illustration tool. It is not investment, tax, or legal advice, and it does not recommend buying or selling any security. Projected outcomes are hypothetical illustrations of the assumptions you enter, not predictions; past performance does not guarantee future results. Consult a licensed fiduciary and a qualified tax professional before making financial decisions. See the Terms, Disclaimer, and Privacy Policy. © Investment Scenario Lab.