RS vs RSI: The Key to Crafting a Winning Trading Strategy (Relative Strength Index)
- FinancialWisdom
- Aug 9, 2025
- 5 min read
Updated: Dec 26, 2025
Learn how to apply RS and RSI to identify trends
One of the most damaging misunderstandings in retail trading is the belief that Relative Strength (RS) and the Relative Strength Index (RSI) measure the same thing.
They do not.
This confusion is subtle, widespread, and expensive. It leads traders to:
Screen the wrong stocks
Avoid genuine market leaders
Enter late or exit early
Spend years analysing noise instead of leadership
Professional traders such as William O’Neil, Mark Minervini, and David Ryan built their results on relative strength, not RSI. Understanding the difference is not optional — it is foundational.
The Core Distinction Most Traders Miss
The simplest way to understand the difference is this:
Relative Strength (RS) compares a stock to other stocks or the broader market
Relative Strength Index (RSI) compares a stock to its own past price behaviour
They answer completely different questions.
RS asks: “Is this stock outperforming most other stocks?”
RSI asks: “Is this stock strong or weak relative to its recent moves?”
One identifies leaders. The other measures momentum conditions.
What Relative Strength Actually Measures
Relative Strength is a ranking and comparison tool.
In its purest form, it ranks stocks by performance over a rolling period — typically 12 months — and compares them to the rest of the market.
William O’Neil formalised this concept by creating a percentile ranking system:
Stocks are ranked from 1 to 99
A stock with an RS rating of 90 has outperformed 90% of the market over the past year
Crucially, this is a rolling calculation, not a calendar-year metric. Rankings update continuously as price action evolves.
O’Neil’s research, spanning from the 1950s through 2008, showed that the average RS rating of the biggest winners before their major advances was 87.
In other words, the largest winners were already leaders before they made their biggest moves.
Why Relative Strength Identifies Leaders Early
Relative strength reveals where institutional capital is concentrating.
During market corrections, stocks with high RS often:
Decline less than the index
Consolidate constructively
Resume leadership quickly
This behaviour is not accidental. It reflects sustained demand from large market participants.
Within the Financial Wisdom framework, relative strength is used as a primary universe filter. Stocks that fail to demonstrate leadership are excluded before any setup analysis begins.
FW Scanner for finding leading stocks:
Practical Relative Strength Without Formal Rankings
Even without a formal RS ranking system, relative strength can be observed through comparison.
Examples include:
Comparing a stock’s performance to a broad index (S&P 500 or NASDAQ 100)
Identifying stocks rising while the market is flat or falling
Observing sector leadership, then ranking stocks within that sector
This process narrows attention to where capital is already flowing, rather than where traders hope it will flow next.
This is also why, within the Financial Wisdom ecosystem, relative strength is embedded into the bespoke breakout scanner, ensuring only leading stocks are surfaced for further analysis.
What RSI Actually Measures (And What It Doesn’t)
The Relative Strength Index is a momentum oscillator.
It measures:
The balance of up days versus down days
Over a fixed lookback period
On a single stock, in isolation
When RSI rises above 70, the stock is considered overbought. When it falls below 30, it is considered oversold.
The mistake most traders make is assuming:
“Overbought means the stock must fall.”
In strong trends, this is false.
Market leaders often remain overbought for extended periods, because sustained demand keeps pushing price higher.
The Correct Role of RSI in a Professional Process
RSI should never be used to select stocks.
That is not its purpose.
Within a professional framework:
Relative strength selects leaders
RSI assists with timing
A practical sequence looks like this:
Identify high RS stocks (leaders)
Wait for constructive consolidation
Use RSI on weekly charts to time pullbacks within the trend
RSI becomes useful only after leadership has already been established.
Why Combining RS and RSI Works (When Done Correctly)
When RS and RSI are used together, each tool does the job it was designed for:
RS answers “What should I focus on?”
RSI answers “When should I act?”
This prevents a common retail mistake:
Applying RSI to random stocks
Mistaking short-term momentum for leadership
Trading overbought laggards instead of institutional leaders
Within the Financial Wisdom framework, RSI is optional — relative strength is not.
Risk Still Comes First
Even when RS and RSI align, risk remains non-negotiable.
Every trade must:
Have a defined invalidation point
Allow sensible position sizing
Fit within broader portfolio risk
No indicator replaces risk management. It only improves selection and timing.
This is why all trades within the Financial Wisdom community are managed transparently, showing how leaders are handled after entry, not just identified beforehand.
The Financial Wisdom Perspective
Relative strength identifies who is winning. RSI helps time how to participate.
Confusing the two leads traders away from leadership and toward randomness.
For those wanting the full methodology — including how relative strength, volatility contraction, trend filters, and risk rules integrate into one process — the Financial Wisdom Strategy Blueprint is available free and details the framework in full.
Key Takeaways
Relative Strength and RSI measure completely different things
RS identifies market leaders
RSI measures momentum within a single stock
Leaders often remain overbought for extended periods
RS should always come before RSI
Risk management remains essential
FAQs
Is Relative Strength the same as the Relative Strength Index?No. Relative Strength compares a stock to other stocks or the market. RSI compares a stock to its own past price action.
Why did traders like Minervini and O’Neil focus on RS instead of RSI?Because RS identifies market leaders under institutional accumulation, while RSI only measures momentum conditions.
Can RSI be useful at all?Yes, but only for timing entries after leadership has been established through relative strength.
Should RSI be avoided on strong trends?No. Overbought RSI readings are common in strong trends and should not be treated as automatic sell signals.
Is relative strength included in the Financial Wisdom breakout scanner?Yes. Relative strength is one of the core filters used to ensure only leading stocks are considered.
Published by FinancialWisdomTV.com Relative Strength | Momentum | Rules-Based Stock Selection
For those interested in using my breakout method and bespoke scanner, why not join us: https://www.financialwisdomtv.com/service
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