Essential Knowledge18 min read

Understanding Backtest Metrics

Master the essential metrics that determine strategy quality. Learn Sharpe ratio, Sortino, maximum drawdown, profit factor, and how to interpret them correctly.

Return Metrics

Total Return

The overall percentage gain or loss from start to finish.

Formula:

Total Return = (Final Value - Initial Value) / Initial Value × 100%

Example

Started with $10,000, ended with $15,000 → Total Return = ($15,000 - $10,000) / $10,000 = 50%

Annualized Return (CAGR)

Compound Annual Growth Rate - normalizes returns across different time periods. More useful than total return for comparing strategies.

Formula:

CAGR = (Final Value / Initial Value)^(1/Years) - 1

Example

$10K → $15K over 2 years

CAGR = ($15,000 / $10,000)^(1/2) - 1 = 22.5% annually

Why CAGR Matters

Always use CAGR when comparing strategies. A 100% return over 5 years (14.9% CAGR) is worse than 80% over 2 years (34.2% CAGR). CAGR accounts for time and compounding.

Risk-Adjusted Return Metrics

Sharpe Ratio ⭐

Most Important Metric

Measures return per unit of volatility. Higher is better. Shows how much excess return you receive for the volatility you endure.

Formula:

Sharpe Ratio = (Return - Risk Free Rate) / Standard Deviation

Sharpe RatioRatingInterpretation
< 1.0PoorLow return for risk taken
1.0 - 2.0GoodAcceptable risk-adjusted returns
2.0 - 3.0ExcellentStrong risk-adjusted returns
> 3.0ExceptionalInstitutional-grade

Real Example

  • • Strategy A: 30% return, 20% volatility → Sharpe = 1.5 (good)
  • • Strategy B: 20% return, 8% volatility → Sharpe = 2.5 (excellent)
  • • Strategy B is better despite lower returns!

Sortino Ratio

Like Sharpe but only penalizes downside volatility. Better for strategies with asymmetric returns.

Formula:

Sortino = (Return - Risk Free Rate) / Downside Deviation

Only counts negative volatility, ignores positive swings

When to prefer Sortino:

Strategies with big wins, small losses (upside volatility is good)

When to prefer Sharpe:

Balanced strategies with symmetric returns

Drawdown Metrics

Maximum Drawdown ⭐

Critical Risk Metric

Largest peak-to-trough decline in account value. Shows worst-case loss you must tolerate.

Formula:

Max DD = (Trough Value - Peak Value) / Peak Value × 100%

Example: Peak $15K, Trough $10K → Max DD = -33.3%

Max DrawdownRatingPsychological Impact
< 10%ExcellentEasy to tolerate
10-20%GoodManageable stress
20-30%ModerateSignificant stress
30-50%HighSevere stress, may quit
> 50%Extreme❌ Unacceptable for most

Recovery Math

  • • -10% drawdown needs +11% to recover
  • • -20% drawdown needs +25% to recover
  • • -33% drawdown needs +50% to recover
  • • -50% drawdown needs +100% to recover

Calmar Ratio

Return per unit of maximum drawdown. Higher is better.

Formula:

Calmar = Annualized Return / |Max Drawdown|

Example: 20% CAGR, 15% max DD → Calmar = 1.33

Values > 1.0 are good (return exceeds max drawdown). Values > 2.0 are excellent.

Trade-Level Metrics

Win Rate

Percentage of trades that are profitable. Simple but misleading if viewed alone.

Formula:

Win Rate = (Winning Trades / Total Trades) × 100%

Win Rate Can Be Misleading

  • • 90% win rate with $10 avg win, $200 avg loss = LOSING strategy
  • • 40% win rate with $300 avg win, $100 avg loss = WINNING strategy
  • • Always evaluate win rate with profit factor and risk/reward

Profit Factor ⭐

Ratio of gross profit to gross loss. Shows dollars made per dollar lost.

Formula:

Profit Factor = Gross Profit / Gross Loss

Example: $12,000 in wins, $8,000 in losses → PF = 1.5

Profit FactorInterpretation$ Made per $ Lost
< 1.0❌ LosingNet loss
1.0 - 1.5Marginal$1.00-$1.50 per $1 lost
1.5 - 2.0Good$1.50-$2.00 per $1 lost
2.0 - 3.0Excellent$2.00-$3.00 per $1 lost
> 3.0Exceptional>$3.00 per $1 lost

Average Win / Average Loss

Shows risk/reward ratio of your trades. Critical for evaluating strategy quality.

Good R:R Examples

  • • Avg Win $200, Avg Loss $100 = 2:1
  • • Avg Win $150, Avg Loss $50 = 3:1
  • • Higher R:R allows lower win rate

Poor R:R Examples

  • • Avg Win $50, Avg Loss $100 = 1:2
  • • Avg Win $80, Avg Loss $200 = 1:2.5
  • • Needs very high win rate (>70%)

Advanced Metrics

Recovery Factor

Net profit divided by max drawdown.

Recovery = Net Profit / |Max DD|

Values > 2.0 are good. Shows if profits justify the pain.

Expectancy

Average $ expected per trade.

= (Win% × Avg Win) - (Loss% × Avg Loss)

Positive = profitable. Higher is better.

Maximum Consecutive Losses

Longest losing streak in backtest.

Important for position sizing. If max = 8 losses, expect 10-12 in live trading (multiply by 1.5×).

Ulcer Index

Measures depth and duration of drawdowns.

Lower is better. More comprehensive than max drawdown alone.

How to Interpret Metrics Together

Good Strategy Example

Good Strategy Example

Returns:

  • • CAGR: 18% ✅
  • • Sharpe: 1.8 ✅
  • • Sortino: 2.4 ✅

Risk:

  • • Max DD: 12% ✅
  • • Calmar: 1.5 ✅
  • • Profit Factor: 2.1 ✅

→ Strong returns with manageable risk. Good Sharpe shows consistency. Low drawdown = low stress.

Risky Strategy Example

Risky Strategy Example

Returns:

  • • CAGR: 35% 🤔
  • • Sharpe: 0.8 ❌
  • • Sortino: 1.1 ❌

Risk:

  • • Max DD: 42% ❌
  • • Calmar: 0.83 ❌
  • • Profit Factor: 1.3 ❌

→ High returns but terrible risk metrics. Sharpe < 1 and 42% drawdown means extreme volatility. Most traders would quit during drawdown.

Metric Priority

  1. 1. Sharpe Ratio - Most important. Shows consistency and risk-adjusted returns.
  2. 2. Maximum Drawdown - Must be psychologically tolerable (ideally <20%).
  3. 3. Profit Factor - Should be >1.5 for confidence.
  4. 4. CAGR - Higher is better, but only after above metrics check out.
  5. 5. Win Rate + R:R - Ensure they're mathematically viable together.

Frequently Asked Questions

What is a good Sharpe ratio?

A Sharpe ratio above 1.0 is considered good, above 2.0 is excellent, and above 3.0 is exceptional. It measures risk-adjusted returns. Sharpe of 1.5 means you earn 1.5 units of return for each unit of volatility. Most successful strategies have Sharpe ratios between 1.0-2.5.

What is maximum drawdown?

Maximum drawdown is the largest peak-to-trough decline in account value. If your account grew from $10K to $15K, then dropped to $12K, max drawdown is $3K or 20% from the peak. Lower is better. Professional strategies target max drawdown under 20-30%.

What is profit factor?

Profit factor = Gross Profit / Gross Loss. It shows how many dollars you make for each dollar lost. Profit factor of 2.0 means you make $2 for every $1 lost. Values above 1.5 are good, above 2.0 are excellent. Below 1.0 means the strategy loses money.

Can I have high returns with low Sharpe ratio?

Yes, but it indicates high volatility. Example: 50% return with 60% volatility gives Sharpe of 0.83 (poor). This strategy has wild swings and is psychologically difficult. Compare to 20% return with 10% volatility (Sharpe 2.0) - lower returns but much smoother, sustainable equity curve.

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