Strategies

How to Test and Adjust Your Trading Strategy

Astron Team · 09/24/2026 · 6 min read

After defining the trader profile that fits you — available time, risk tolerance, capital, and personality — the next step is putting the chosen strategy to the test before trading meaningful amounts. This is the stage where a lot of people jump straight to real money, driven by the eagerness to get started, and end up paying to learn lessons a simple test would have already shown for free.

This is the second part of the guide on how to choose a trading strategy. Here the focus is practical: how to test a strategy on historical data, how to adjust risk based on that test, and how to know, with criteria, when it's time to switch strategies.

A simple backtest, no programming needed

A backtest is just applying the strategy's rules to data that has already happened, to see how it would have behaved. You don't need expensive software to get started: a historical chart and a spreadsheet already do the job. Choose the asset, define the exact entry and exit rules (for example, buy when the price crosses above the 20-period moving average, and exit with a 2% target or a 1% stop), and manually go through the last six to twelve months of the chart, noting every signal the rule would have generated.

Record, for each signal, whether the result would have been positive or negative and by how much. With 30 to 40 signals logged, you can already calculate two simple metrics: the win rate (how many trades would have been positive, divided by the total) and the average result per trade. A strategy with a 40% win rate, for example, can still be profitable if the gains are, on average, bigger than the losses.

How to adjust risk after the test

The backtest also helps calibrate position sizes. Suppose R$ 2,000 in capital and a rule to risk 1% per trade, which equals R$ 20. If the test showed a streak of up to five consecutive losses in the analyzed period, it's worth simulating that scenario: five losses of R$ 20 add up to R$ 100, about 5% of capital. If that amount seems manageable, the 1% risk per trade is reasonable for that profile; if it seems too heavy, it's time to lower the risk per trade before trading with real money.

This adjustment isn't a one-time thing. As capital changes, or as the asset's volatility increases or decreases, the risk amount per trade should be recalculated, always as a fixed percentage of current capital, never as a fixed amount in money that becomes outdated over time.

When to switch strategies, with criteria

Switching strategies every time a trade goes wrong is one of the most common mistakes among beginners, and it tends to worsen the result, because the person never accumulates enough signals to seriously evaluate anything. The criteria for switching strategies should be statistical, not emotional: if after 30 or 40 trades strictly following the rule the accumulated result remains negative, and there's been no relevant change in market conditions, then it makes sense to review or replace the strategy.

It's also worth switching when market conditions change structurally: a strategy designed for trending markets, for example, tends to produce poor results during long sideways periods, and sticking with it in that scenario is different from the strategy simply being wrong.

Documenting to learn from your own history

Keeping a record of every trade — asset, date, reason for entry, result, and a note on what was or wasn't strictly followed — is what turns months of trading into real learning. Without this record, every mistake repeats because there's no way to identify the pattern. With the record, you can answer concrete questions, like whether losses cluster at a certain time, on a certain type of asset, or right after a big win, when confidence tends to rise more than it should.

Testing, adjusting, and documenting aren't steps you do once and forget: they're a continuous cycle. Every batch of trades — whether in stocks, currencies, or indices, including on platforms like Astron — generates new data to review risk and confirm, or not, that the strategy chosen in the first part of this guide still makes sense for your profile.