What is technical analysis?
Lesson 44 · practical guide
Technical analysis uses historical price and volume to describe behaviour and build trade hypotheses. It can help plan entries and exits, but patterns are not laws and can fail when liquidity, news or regime changes.
What you will learn
Read a price chart as evidence about behaviour, not as a machine that predicts the future.
Key terms
- Candle — a visual summary of open, high, low and close for a period.
- Support and resistance — areas where past trading showed changing demand or supply.
- Backtest — testing a rule on historical data.
Follow these steps
- Choose a timeframe that matches the decision horizon.
- Record the rule precisely so another person could apply it without interpretation.
- Include spread, fees, slippage, survivorship and look-ahead bias in testing.
- Use an out-of-sample or simulated period before risking money.
Practical advice
A pattern becomes useful only if it improves a defined decision after costs. A chart can show what happened; it cannot guarantee why it happened or what comes next.
Long-form explainer
The full guide
Read this lesson as a chapter: understand the mechanism, test the assumptions and apply the idea with a clear risk limit.
A price chart is a record of behaviour
A candle summarises the open, high, low and close for a period. Support and resistance describe areas where buying or selling previously influenced price; they are zones, not guaranteed walls. A chart can reveal trend, range, momentum and volatility, but it cannot tell you with certainty what will happen next.
The timeframe changes the story. A move that looks dramatic on a short chart may be ordinary in a longer series, while a small-looking move can matter to a leveraged position. Start with the decision horizon and choose a chart that matches it.
Test a chart rule honestly
Define the pattern, entry, exit, size and invalidation before looking for examples. A backtest should include costs, spreads, slippage, delisted assets where relevant and periods that were not selected because they looked attractive. Avoid changing the rule after every losing example.
Use charts as one input alongside liquidity, fundamentals, news risk and execution constraints. A pattern that appears in hindsight may be difficult to trade live. The value of technical analysis comes from a repeatable rule with known limitations, not from a more complicated drawing.
What usually goes wrong
The first mistake is finding the pattern after the outcome. Any chart contains support, resistance and a trend line that explains what already happened, and constructing the explanation afterwards feels exactly like analysis while proving nothing. The second error is adding indicators until something agrees. Most indicators are transformations of the same price series, so stacking them produces the illusion of independent confirmation rather than real evidence.
People also test rules dishonestly, adjusting parameters until past data looks good and mistaking that fit for predictive power. A rule with many settings will always describe history well; the question is whether it survives on data it has never seen, after costs. A related failure is changing the timeframe after a trade goes against them, moving from a fifteen-minute chart to a daily one to find a reason the position is still fine. The final mistake is using charts without position sizing. A method that identifies decent setups still loses money if each one is sized by conviction rather than by risk.
How it works
Start with one question: trend, range, volatility, liquidity or execution. Define indicators before looking at the result. A moving average or oscillator transforms past data; it does not create certainty about the future.
Backtest with realistic spread, fees, slippage, missed fills and delisted assets. Avoid changing parameters until the historical result looks attractive; that is overfitting.
Worked example
Numbers make an idea concrete. Here is a small, illustrative one — not a forecast.
A breakout on low volume with a widening spread may be less actionable than a move supported by deep liquidity. The chart cannot guarantee execution.
Before you act
Run through these questions before you commit any money or make a decision based on this lesson:
- What exact behaviour am I testing?
- What data and sample are used?
- Are costs and missed fills included?
- When is the signal unreliable?
Practice this lesson
Reading is a start; doing the exercise is what makes the idea stick.
Write a chart rule with entry, exit, invalidation and no-trade conditions. Test it on data not used to create it.
Further reading
Educational content only: This guide is not personal financial, legal or tax advice. Markets involve risk, including the possible loss of capital. Verify current rules, fees and product availability in your country.