What it is
When you change a strategy setting, a policy rule, or a stop/target distance, you might expect Tessera to show you a neat before-and-after on your existing trades. That is only part of the story. In live trading and in algorithmic systems, a small change often changes which trades you take at all - and that can cascade into a completely different set of outcomes. This article explains that distinction so you can use reports, policies, and the simulator with the right expectations.
What you can do
- Understand what counterfactual tools (simulator, exit replay, entry filters on past trades) can and cannot tell you
- See why a policy that looks great on past trades may behave very differently once you trade live with it
- Choose the right tool: reports for what happened, simulator for “what if on the same trades,” not for predicting the future
How it works
Two different questions
Tessera’s analysis tools answer two very different questions:
| Question | Example | Tools that help |
|---|---|---|
| What happened? | “How did I perform in London sessions last quarter?” | Reports, Statistics, Trade Log |
| What if on the same trades? | “If I had skipped trades when volatility was high, how would my numbers change?” | Reports, Simulator |
A third question - “What will happen if I change my live strategy?” - is not something Tessera can answer from past data alone. That is because changing your rules changes future entries, not just how you manage trades you already took.
The cascade effect
Imagine you have five trades in a week. You add a filter: “only take trades when the market is trending.”
On past data, the simulator might show: “Trade 3 and Trade 5 would have been removed - your win rate improves.”
In live trading, removing Trade 3 might mean you never reach the mental or capital state that led to Trade 5. Or a different signal fires on Tuesday that you would have ignored before. By Friday you might have taken different trades entirely - not just fewer of the same ones.
This is especially true with algorithmic or rule-based approaches: entry logic, position sizing, and sequencing are linked. Changing one knob does not slide a single curve; it can switch you onto another path.
What “replay” means in Tessera
The simulator and Exit Placement features replay your existing closed trades. They can:
- Filter which of those trades count (entry conditions at the moment you entered)
- Replay exits with different stop-loss or take-profit distances on those same entries
They do not:
- Re-run your TradingView or broker strategy bar by bar
- Invent trades you never took
- Model how a live rule change would alter your future trade sequence
See Simulator overview for the full list of limits.
Reports vs policies vs simulator
- Reports analyse a fixed set of closed trades in a date range (a cohort). They describe what actually happened.
- Policies are rules you build from report insights - entry filters or exit distance changes.
- Simulator tests those rules against the same cohort the report used. It does not test “tomorrow.”
If you publish a policy to live trading, the next month’s trades may not resemble the cohort you tested on. That is normal - not a bug in the simulator.
Limitations
- No analytics product can fully predict how a rule change will reshape your future trade list.
- Counterfactual results are informative, not authoritative. Use them to explore ideas, not as guaranteed performance claims.
- Entry-only filters change which trades count in metrics; they do not change the PnL of individual trades unless you are in exit-replay mode.