Direct answer: what “worked example” means for RSI strategies
A “worked example” of RSI strategies is a transparent, number-based scenario that shows how RSI is calculated and how specific, pre-defined RSI conditions could be expressed as rules for analysis—without assuming profit. The key is that every input and assumption (prices used, RSI period, smoothing method, threshold values) is stated so another reader can reproduce the same RSI values.
Mechanism and definition: what RSI is (and what it isn’t)
Relative Strength Index (RSI) is a momentum oscillator that summarizes the magnitude of recent price gains versus losses over a lookback window (commonly 14 periods). Conceptually:
- Compute the average gain and average loss over the chosen lookback.
- Convert those to a relative strength ratio.
- Map the ratio to an oscillator scale (often 0 to 100).
RSI strategies (in an informational sense) generally mean “using RSI readings inside a defined rule set,” such as checking whether RSI is above or below certain levels, or whether it crosses a threshold, or whether RSI changes direction. An important distinction: RSI is a measurement tool. It is not, by itself, a standalone signal that guarantees a particular market outcome.
Worked example: calculate RSI step by step with explicit assumptions
Assumptions for this worked example (all fixed for reproducibility):
- We use 1-step price changes (each “period” is one consecutive observation).
- We choose an RSI lookback period of 5 (shorter than typical 14 so calculations fit in one example).
- We use simple averages of gains and losses over the last 5 periods (no special smoothing).
- We compute RSI using the common formula: RS = AvgGain / AvgLoss, RSI = 100 − (100 / (1 + RS)).
- If AvgLoss = 0, RS is treated as infinite, so RSI becomes 100.
Scenario prices (arbitrary, not live data):
- P0=100.0, P1=102.0, P2=101.0, P3=103.0, P4=104.0, P5=103.0
Step 1: compute gains and losses for periods 1 to 5 (differences from the previous price):
- P1−P0 = +2.0 → gain 2.0, loss 0.0
- P2−P1 = −1.0 → gain 0.0, loss 1.0
- P3−P2 = +2.0 → gain 2.0, loss 0.0
- P4−P3 = +1.0 → gain 1.0, loss 0.0
- P5−P4 = −1.0 → gain 0.0, loss 1.0
Step 2: average over the last 5 periods:
- AvgGain = (2.0 + 0.0 + 2.0 + 1.0 + 0.0) / 5 = 5.0/5 = 1.0
- AvgLoss = (0.0 + 1.0 + 0.0 + 0.0 + 1.0) / 5 = 2.0/5 = 0.4
Step 3: compute RS and RSI:
- RS = 1.0 / 0.4 = 2.5
- RSI = 100 − (100 / (1 + 2.5))
- RSI = 100 − (100 / 3.5) ≈ 100 − 28.571 ≈ 71.43
How this becomes a “strategy rule” for analysis (still not a guarantee):
- Example rule A (threshold condition): “Flag the window if RSI > 70.”
- With the computed RSI ≈ 71.43, the condition is true for this scenario.
- Example rule B (cross condition): “Flag only when RSI crosses above 70 from below.”
- This requires RSI values from an earlier window too; without that earlier RSI, the cross cannot be verified.
What a reader can independently verify:
- Recompute all price differences.
- Recompute AvgGain and AvgLoss using the stated averaging method.
- Recompute RSI from the stated RS-to-RSI mapping.
Limitations and risks: material failure modes to expect
Several limitations can cause RSI-based conditions to behave differently than expected:
- Market regime changes: RSI reflects recent gains/losses. When volatility expands or the character of price moves changes, the same RSI threshold may correspond to different underlying behavior.
- Trend environments: In persistent trends, RSI can remain high or low for extended periods, making simple threshold rules frequent and less informative.
- Execution and costs: Even when RSI conditions are correctly computed, real outcomes depend on costs (spreads/fees), latency, and order execution. Small differences can change results.
- Formula and implementation differences: Different RSI implementations may use specific smoothing (often Wilder’s smoothing), rounding rules, and different period definitions. If you change those assumptions, RSI values can change.
Verification or next question: how to check RSI-strategy claims
To verify any RSI strategy description independently, check whether it states:
- The RSI period (lookback length) and exact RSI calculation method.