Forecasting, explained.

Forecast. Experiment. Understand.

Don't just see the forecast. Understand what moves it.

DClaw Forecast studies historical data to estimate what may happen next — then lets you change assumptions and see how the prediction responds.

Use it for economic indicators, markets, weather, sales, demand and other time-series data.

  1. Past data
  2. Forecast
  3. Try a change
  4. Compare
  5. Understand

Try it yourself

A small working lab. Change one thing and watch the forecast respond. Or watch a two-minute silent tour of the whole app.

  1. 1
    Pick a worldGDP, stocks or weather.
  2. 2
    Change one thingDrag the assumption, then the window for when it applies.
  3. 3
    Run itPress Run experiment to compare against the baseline.
  4. 4
    Read what movedEvery number on the right is calculated from that run.
DClaw Forecast Lab · demo
DemoGDP growth · example economy
1.00%1.50%2.00%2.50%3.00%Scenario activeForecast startBaselineExperiment2023 Q12026 Q22027 Q12027 Q42028 Q4
Interest rate assumptionInterest rate assumptionWhat is this?The future interest-rate path supplied to the forecasting scenario.Potentially affectsForecastScenario pathModel response over timeTime range2027 Q1 → 2027 Q4This is an assumption, not a model hyperparameter.Learn more
Baseline4.0%Experiment5.0%
Apply2027 Q1 2027 Q4

Scenario active for 4 quarters. After the period: return to baseline.

What changed?
Value
4.0% → 5.0% (+1 pp)
Timing
Starts 2027 Q1
Duration
4 quarters, then return to baseline
Observed
Largest difference
−0.32 pp in 2027 Q4
Average during scenario
−0.25 pp
Average after it ends
−0.07 pp
Uncertainty width
+4.6%

Calculated from this demo run. Change anything to run a new experiment.

Change one thing. See what moves.
How this demo works

Example data, not live economic statistics. Demo rule: each +1 pp in the rate lowers growth by up to 0.35 pp; the effect builds over the first quarters of the window and halves every quarter after it ends. Invented for illustration — not an estimated economic relationship.

What if interest rates rise from 4.0% to 5.0% for four quarters?

This is the kind of question DClaw Forecast is built for. Here is what it does with it, using the demo above.

Your change
Interest rate
4.0% → 5.0%
Starts
2027 Q1
Ends
2027 Q4
Then
Returns to normal
It compares two forecasts
Baseline: the forecast before your change Your scenario: the forecast after it
Then it shows you
How the forecast changed
−0.32 pp at most
When the biggest difference appeared
2027 Q4
How uncertainty changed
range +4.6% wider
How the model did on past data
0.16 pp typical miss vs 0.95 for a simple guess*
Why the output moved
Only the interest-rate assumption changed

Demo figures, not real economic data. *The past-data score is the Lab's GDP model tested on 8 held-out quarters of its sample data, against assuming average growth.

How DClaw Forecast works

Six steps, the same for every kind of data.

  1. Add your data

    Start from a built-in example or upload your own history as a CSV.

    • GDP history
    • Stock prices
    • Weather observations
    • Monthly sales
    • Customer demand

    Monthly, weekly or daily data. Weekly and daily values are combined into months, because forecasts here are monthly.

  2. Choose what to forecast

    Pick the number you care about.

    • GDP growth
    • Stock return
    • Temperature
    • Monthly sales
  3. Create a baseline

    The model estimates what may happen next if nothing in your experiment changes.

  4. Try something different

    Change an assumption, a model setting or how far ahead to look, plus when a change starts and how long it lasts.

  5. Compare

    See the baseline and your experiment side by side.

  6. Understand

    What changed and when, how uncertain it is, how well the method did on past data, and why it responded.

What is a forecast?

A forecast is an estimate of what may happen in the future, based on patterns in historical data and, where supported, additional inputs or assumptions.

A forecast is not a guarantee. That's why DClaw also shows:

  • Uncertainty: the range of outcomes the model considers plausible
  • Historical validation: how well the method did on past data
  • Assumptions: exactly what you asked it to assume
  • Model settings: how the method was set up
Your data
  • GDP
  • Stocks
  • Weather
  • Sales
Forecast model

Finds patterns such as:

  • TrendTrendTechnical name: trend component / slopethe long-run direction
  • SeasonalitySeasonalityTechnical name: seasonal componenta rhythm that repeats every year
  • RelationshipsRelationshipsTechnical name: exogenous regressors / featureshow one series moves with another
  • Recent behaviourRecent behaviourTechnical name: smoothing / lagged valueswhat the last few periods did
Forecast

The expected future path

Uncertainty

The range of plausible outcomes

What can you forecast?

The steps stay the same, but the experience adapts to the kind of data: quarterly economics, daily markets, uncertain weather, seasonal business numbers.

In the LabWith your own monthly dataNot yet available

Economy

“What if interest rates stay higher for longer?”

  • In the Lab: GDP
  • In the Lab: Inflation (as an input)
  • In the Lab: Unemployment (as an input)
  • With your own monthly data: Industrial production

Quarterly data. In the Lab it runs on official US statistics. You set the future path of interest rates, inflation, business activity and unemployment, then see which input moved GDP and by how much.

Markets

“Can yesterday's move predict tomorrow's?”

  • In the Lab: Stock prices
  • In the Lab: Daily returns
  • In the Lab: Volatility
  • In the Lab: Indices
  • With your own monthly data: Commodities

Daily prices (the S&P 500, Nasdaq and Dow in the Lab), technical features like moving averages and RSI, and every model scored on days it never saw, so you can tell a real signal from noise.

Weather

“How much less certain is the forecast a year out than next month?”

  • In the Lab: Temperature
  • In the Lab: Rainfall
  • In the Lab: Cloud cover
  • In the Lab: Peak wind
  • In the Lab: Humidity
  • In the Lab: Sunshine

Six measures (high temperature, rainfall, cloud cover, peak wind, humidity and sunshine), each as a range instead of a single number (low, middle and high cases), with each month's sky and season read from the forecast. In the Lab it runs on real observed weather for five Indian cities.

Business

“What if demand jumps during the holiday period?”

  • In the Lab: Revenue
  • In the Lab: Product demand
  • With your own monthly data: Sales
  • With your own monthly data: Website traffic
  • With your own monthly data: Support volume

Monthly data with a yearly rhythm. Add a promotion or a one-off event, choose when it starts and how long it lasts, and compare.

Start with sample data Sample data: SaaS Revenue

Operations

“How much demand might we need to plan for next month?”

  • In the Lab: Staffing (headcount)
  • In the Lab: Inventory, from demand
  • With your own monthly data: Energy demand
  • With your own monthly data: Transport demand

The same monthly engine read as a planning range: the middle is the likely need, and the shaded range tells you how much buffer to hold.

Start with sample data Sample data: Electronics Demand

What can I experiment with?

Two kinds of change, kept visibly apart.

Real-world assumptions

Change the scenario you want to test.

  • Interest rates“What if rates rise 1 point?”
  • Inflation“What if it stays high for a year?”
  • Promotion or one-off event“A 20% launch spike in March”
  • Expected demand“What if demand runs 10% hotter?”
  • Scenario period“Only for these four quarters”

Model settings

Change how the forecasting method learns from the data.

  • How far into the future should we predict?forecast horizon
  • How quickly should the model update its growth rate?trend smoothing (β)
  • How quickly should the seasonal pattern update?season smoothing (γ)
  • Which forecasting method?model
  • How much history should the model learn from?training window

Change not just what — but when.

The same change can produce a different model response depending on when it happens and how long it lasts.

Interest rate
What changes
From
4.0%
To
5.0%
Start
2027 Q1
End
2027 Q4
Then
Return to baseline
Baseline
Scenario
Return to baseline

How does the change unfold?

Step all at once
Gradual builds up
Temporary fades away
Custom you draw it

Was it the size of the change, or how long it lasted?

Experiment A+1 pp · 4 quarters
Biggest difference
−0.32 pp
Added up over time
−1.31 pp
Experiment B+1 pp · 8 quarters
Biggest difference
−0.35 pp
Added up over time
−2.38 pp
Experiment C+2 pp · 4 quarters
Biggest difference
−0.64 pp
Added up over time
−2.62 pp

Three demo experiments on the GDP example, each starting 2027 Q1. In the Lab you choose the start, the length, the shape and what happens afterwards.

Baseline vs experiment

Baseline
The forecast before your experiment.
Experiment
The forecast after applying your changes.
Difference
The gap between the two, period by period. That gap is what your change did.
differencebaselineexperiment
Baseline4.0%interest rate held at its baseline path
Experiment5.0%2027 Q1 → 2027 Q4, then back to baseline
Demo data · disclosed demo rule
−0.30 pp−0.20 pp−0.10 pp+0.00 ppScenario activeBeforeDuringAfterForecast startBaseline = 02023 Q12026 Q22028 Q4
Largest forecast difference
−0.32 pp
2027 Q4
Scenario-period impact
−0.25 pp
average, during
Post-scenario impact
−0.07 pp
average, after it ends
Uncertainty change
+4.6%
average interval width

How uncertain is this prediction?

The shaded area shows a range of outcomes the model considers plausible. It gets wider the further ahead you look, because small errors add up over time.

  • The line is the most likely path.
  • The shaded range is where the actual value will probably land.
  • You choose how wide: cover 80%, 90% or 95% of plausible outcomes.

Technical: prediction interval, or a quantile range such as P10–P90.

PastFutureplausiblerangemost likely path
Demo series. Near-term forecasts have a tighter range than far-ahead ones.

Why did it change?

Every change is listed, and so is everything that stayed the same. The response is calculated, never guessed.

Why did my forecast change?
Changed assumption
Interest rate 4.0% → 5.0%
When
2027 Q1 → 2027 Q4
Model settings
Unchanged
How far ahead
Unchanged · 10 quarters
Model responseLargest difference from the baseline−0.32 pp in 2027 Q4

Demo run. The difference is calculated; no cause is claimed beyond the assumption you changed.

What might happen

Before running it · guidance only

  • Growth may move below the baseline during the window
  • Some of the effect may persist after the window ends
  • The uncertainty range may widen
What actually happened

After running it · calculated

Largest difference from baseline
−0.32 pp
Average after the window ends
−0.07 pp
Uncertainty range, average width
+4.6%
When the biggest difference appeared
2027 Q4

How well did this method work on past data?

Before trusting a forecast, test it. Hide the most recent months, let the model predict them, compare with what actually happened, then move forward and repeat. Below is the Lab's real test on the Electronics Demand sample data (ARIMA model).

  1. Learn from Oct 2022 – Sep 2024 Test on Oct 2024 – Dec 2024 typical miss 14,479
  2. Learn from Oct 2022 – Dec 2024 Test on Jan 2025 – Mar 2025 typical miss 17,750
  3. Learn from Oct 2022 – Mar 2025 Test on Apr 2025 – Jun 2025 typical miss 2,137
  4. Learn from Oct 2022 – Jun 2025 Test on Jul 2025 – Sep 2025 typical miss 1,050
Average errorAverage errorAverage size of the prediction error.Technical name: MAE (mean absolute error)
8,249
Large-error sensitivityLarge-error sensitivityPrediction error that penalises larger misses more strongly.Technical name: RMSE (root mean squared error)
8,854
Average % errorAverage % errorAverage percentage error. Can be unreliable when values are near zero.Technical name: MAPE (mean absolute percentage error)
8.0%
Range coverageRange coverageHow often the actual value fell inside the model's interval.Technical name: interval coverage
67%

Technical name for this kind of test: rolling-origin backtesting (time-series cross-validation).

Every setting explains itself.

Hover the info icon for what a setting is, why it matters and what happens if you raise or lower it. Or switch on Help mode and every term explains itself where you meet it.

Trend smoothing (β)What is it?How quickly ETS updates its estimate of the growth rate.Why does it matter?A small change in the growth rate adds up over every month of the forecast.If you increase it
  • The slope adapts quickly to recent growth or decline
  • Long-horizon forecasts can fan out more
  • Overfitting risk rises on short series
If you decrease it
  • A steadier, long-run slope
  • Far-horizon forecasts stay closer to the historic trend
May affectTrendHorizon behaviourRMSEOverfitting riskLearn more Technical name: ets.beta
How quickly the model updates its growth rateets.beta
0.10
Expected

Move the slider to see what the change is expected to do — the Lab then measures what it actually did.

Real parameter from the Forecast Lab's registry · ETS · Ensemble

Help mode
  • Large-error sensitivity RMSE8,854

    Prediction error that penalises larger misses more strongly.

  • Range coverage coverage67%

    How often the actual value fell inside the model's interval.

  • Shaded range 95% prediction interval95%

    The shaded range showing where future values may reasonably fall.

  • Trend smoothing (β)0.10

    How quickly ETS updates its estimate of the growth rate.

With Help mode on, parameters, metrics and chart layers explain themselves in place — no leaving the app to look up a term. Values shown are the Lab's Electronics Demand sample.

Questions you can answer

Friendly on day one. Powerful when you need it.

You don't need to be a data scientist. Start in Beginner mode; switch to Advanced when you want more control.

Beginner friendly

  • Plain-English controls
  • Hover explanations
  • Guided experiments
  • Simple scores

Powerful when you need it

  • Advanced model settings
  • Historical testing
  • Sensitivity analysis
  • Scenario paths
  • Model comparison
  • Experiment history

Which settings does the forecast react to most?

Slide one setting across its range and re-run the forecast at every value. Computed from the Electronics Demand sample data with the ETS model. Technical name: sensitivity analysis.

How quickly the level updates (α) vs the forecast
α 0.05current 0.40.95
How quickly the level updates (α) vs past-data error
α 0.05current 0.40.95
Measured effect on past-data error
  1. Model19,787
  2. Trend smoothing (β)6,306
  3. Level smoothing (α)5,464
  4. Season smoothing (γ)1,450
  5. How much history to learn from705
  6. Forecast horizonno effect

Which method did best on past data?

Different methods make different trade-offs. Compare them on the same historical test. Scores below are real, from the Electronics Demand sample data.

MethodAverage errorAverage errorAverage size of the prediction error.Technical name: MAELarge-error sensitivityLarge-error sensitivityPrediction error that penalises larger misses more strongly.Technical name: RMSERange coverageRange coverageHow often the actual value fell inside the model's interval.Technical name: coverageStatus
Linear4,4574,6303/12In the Lab
ETS (Holt-Winters)3,5363,70510/12In the Lab
Theta4,0554,4615/12In the Lab
Seasonal naive21,58221,59912/12In the Lab
ARIMA8,2498,8548/12In the Lab
Ensemble3,9964,1598/12In the Lab
Prophet———Planned
Random Forest———Planned
XGBoost———Planned

Why DClaw Forecast?

Most forecasting tools show you a line. DClaw helps you answer:

  • What produced this forecast?
  • What assumptions were used?
  • How uncertain is it?
  • What happens if I change something?
  • Which periods changed the most?
  • Did accuracy on past data improve or get worse?
  • Can I reproduce the experiment?
No black box
See the data, the assumptions and the model behind every number.
No fake certainty
Every forecast comes with a range, not just a line.
Tested, not trusted
Every method is scored on past data it didn't see.
Guidance kept apart
What might happen is labelled as guidance; what did happen is calculated.
Nothing invented
Demo and sample data are labelled as such, everywhere.
Reproducible
Save an experiment and run it again later.

Only in DClaw Forecast

Beat the model
Six real months are hidden. Draw your guess, then see who was closer, and whether your own ranges are honest.
Time machine
Go back to any month and see what the forecast said then, against what actually happened.
Say it in words
Type “a 10% promotion in months 4–6” and get visible, editable settings. Nothing hidden.
1,000 possible futures
See the uncertainty as many paths, with the live chance of hitting your target.

Try them in the Forecast Lab (free, sign in with email or Google).

The goal isn't to make the future certain.
It's to make the forecast understandable.

The future is uncertain.
Your forecast shouldn't be mysterious.

Build a baseline, change an assumption and understand how the model responds.

Economy, markets and weather are in the Lab, plus business and operations data on monthly samples or your own uploads.