What is Correlation?
Correlation measures how closely two assets, markets, or strategies move in relation to each other. It usually ranges from -1 to +1, where positive values indicate similar movement and negative values indicate opposite movement.
How Correlation Works
Correlation measures how closely two assets, markets, or strategies move in relation to each other. It usually ranges from -1 to +1, where positive values indicate similar movement and negative values indicate opposite movement.
The concept should be evaluated using a clear definition, a consistent measurement method, and the same market or account context. Traders often make mistakes when they use the term casually without recording how it was calculated or classified.
A reliable journal entry should preserve the original plan, the actual execution, and the final outcome. When the concept affects risk or performance, the trader should also record fees, slippage, market conditions, and any rule changes that occurred during the trade.
Quick Reference
- Main purpose: Understand and apply correlation consistently.
- Important inputs: Strategy rules, market condition, account size, costs, and risk.
- Useful journal fields: Planned value, actual value, reason, result, and lesson.
- Main limitation: One trade or one period may not provide enough evidence.
- Best practice: Compare similar trades using the same definition.
Example Calculation
Assume two strategies show a historical correlation of +0.85. This suggests their returns often move in the same direction.
If both strategies risk 1% at the same time, the combined portfolio may behave more like one concentrated 2% exposure than two independent trades. The trader should review common drivers and simultaneous drawdown.
Correlation vs Causation
Correlation vs Causation are related ideas, but they answer different questions. The distinction matters because traders may draw the wrong conclusion when they combine them.
A useful comparison should examine definition, timing, risk, cost, and practical application. The trader should keep both concepts in separate journal fields where possible so performance can be analysed without mixing unrelated effects.
The correct choice depends on the strategy, market, timeframe, and objective rather than one universal rule.
Correlation Trading Strategies
Practical methods involving correlation should be written before the trade or investment begins. The plan should define entry conditions, risk limits, invalidation, maximum exposure, and review criteria.
Different strategies may use the concept in different ways. A short-term trader may focus on execution and slippage, while a long-term investor may focus on valuation, allocation, and holding period.
Any major change should be treated as a new strategy version and tested separately. Changing several variables at once makes it difficult to identify what improved or damaged performance.
Why Correlation Matters
Correlation matters because it can affect risk, return, execution, and the interpretation of trading performance. A result that appears strong may become weaker after costs, drawdown, or rule violations are considered.
The concept is also useful for comparing planned behaviour with actual behaviour. If a trader repeatedly records different values from the plan, the problem may be execution rather than strategy.
In Trade Diary, the relevant information can be connected with strategy tags, risk, screenshots, and rules so the trader can identify repeated patterns over time.
Correlation Benchmarks
Useful benchmarks for correlation include:
- Average result across a meaningful sample.
- Best and worst observed outcome.
- Performance after fees and slippage.
- Drawdown and recovery duration.
- Rule-compliance rate.
- Results by strategy and market condition.
- Difference between planned and actual execution.
- Stability across rolling periods.
A benchmark should provide context rather than act as a guarantee. Future outcomes may exceed historical best and worst values, so risk controls should include a safety buffer.
Common Mistakes With Correlation
A common mistake is judging correlation from one trade, one chart, or one short period. Another mistake is using inconsistent definitions across the journal.
Traders may also ignore costs, sample size, market regime, and rule compliance. These omissions can make a weak process appear strong or a valid strategy appear broken.
The best correction is to use fixed fields, preserve original decisions, and compare similar cases before changing the rules.
Practical Review Questions
Before completing the review of correlation, ask:
- Was the concept defined before the outcome was known?
- Were all fees, costs, and risk changes included?
- Did the trade follow the documented strategy?
- Is the conclusion supported by several similar examples?
- Did market conditions affect the result?
- What one action should be repeated or changed?
These questions help convert a glossary concept into a practical trading decision rather than leaving it as a general definition.
Apply Correlation in your trading journal
Keep the original plan, relevant value or condition, execution details, screenshots, and final lesson connected to the same trade. Review the supplied benchmarks and mistakes across a meaningful sample rather than judging the concept from one outcome.
Correlation review and journal checklist
Before applying this concept, confirm that the definition, calculation, market, instrument, timeframe, and data source match the decision being made. Record the value or condition that existed before entry rather than reconstructing it after seeing the result. If broker, exchange, margin, contract, or tax rules affect the concept, verify the current official terms instead of relying on a general example.
After the trade, preserve actual execution, costs, position changes, and the final outcome separately from the plan. Review whether correlation was interpreted consistently and whether the related rule was followed. A profitable outcome should not excuse an undefined process, and a losing outcome should not automatically invalidate correct application.
Use several comparable records before changing a strategy. Note the sample period, filters, exclusions, relevant market conditions, and unanswered questions. Convert the finding into one measurable next action, then test that action without changing several unrelated variables at the same time.
- The original value, condition, or definition is preserved.
- The source and timing of the information are recorded.
- Planned and actual decisions remain separate.
- Costs, risk, and limitations are included.
- The conclusion is supported by comparable examples.
Correlation FAQ
Correlation measures how closely two assets, markets, or strategies move in relation to each other. It usually ranges from -1 to +1, where positive values indicate similar movement and negative values indicate opposite movement.
Traders use this concept to describe, measure, plan, execute, or review a specific part of market activity. Its exact use depends on the instrument, strategy, timeframe, and broker or exchange rules.
Yes, provided the definition is connected to a practical example and its limitations are understood. Beginners should verify product-specific details before applying it.
No. A trading term or measurement does not guarantee an outcome. It should be considered with strategy rules, risk, costs, liquidity, and market context.
Use a consistent field, tag, screenshot, or note when the concept is relevant. Preserve the planned value and actual result separately so the decision can be reviewed later.