Entry Logic
The entry signal fires without certainty. That is not a flaw in the design. It is the condition under which the entire system operates.
A motion sensor has no idea what it has detected.
It does not know whether the movement outside your house was a burglar, a possum or a branch moving in the wind. It does not assess intent. It does not weigh the evidence. It does not sit there wondering whether this particular movement looks more convincing than the last one.
It has a threshold.
The threshold is crossed.
It fires.
What happens next belongs to other mechanisms.
Entry logic in a systematic trend following programme is much the same.
A price breaks above a channel. A moving average is crossed. A volatility boundary is penetrated. The condition has been met, so the system enters.
It does not know whether it has just caught the first few steps of the trend that will define the year or another piece of market noise that will reverse three days later.
It cannot know.
And that is the first thing we need to understand about entry logic.
The inability to distinguish a genuine trend from a false signal at the moment of entry is not a defect we need to engineer away. It is the operating condition of trading a complex adaptive system.
The architecture is built around that fact.
The initial stop contains the loss when the signal fails. Position sizing makes that loss small enough to survive repeatedly. The trailing exit allows the rare winner to keep going. Diversification spreads the search across markets. The ensemble spreads it across different ways of detecting emerging directional movement.
The entry does not need to know the future.
It needs to get us into the game.
What the Entry Is Actually Doing
We tend to ask too much of entries.
Much of trading culture treats the entry as a prediction. Gather enough evidence, refine the indicators, add confirmation, and eventually we should be able to identify the point at which the probability of a successful trade becomes sufficiently high.
The better the entry, supposedly, the more often it should be right.
That sounds reasonable.
For an Outlier Hunter, it is the wrong objective.
At the beginning, the extraordinary trend and the failed breakout can look remarkably similar. Both may cross exactly the same threshold. Both may initially display momentum. Both may appear to be escaping an established range.
Only later does their path separate.
One reverses.
The other keeps going.
Perhaps it accelerates. Participants reposition. Stops are triggered. Narratives change. Capital moves. Feedback begins to reinforce feedback. What looked like an ordinary price movement becomes something else entirely.
But by then the easy uncertainty has disappeared.
And much of the opportunity has already happened.
That creates an uncomfortable requirement for anyone trying to capture outliers:
You must enter before you know.
The entry signal therefore has a much narrower job than most traders give it.
It detects a condition.
That is all.
A level has been broken. Momentum has changed. Price has moved sufficiently far from some reference point. Whatever rule we have chosen has been satisfied.
The entry converts that event into a position.
From that moment onwards, responsibility passes through the architecture. Position sizing determines how much exposure we carry. The initial stop defines the intended loss boundary if the trade immediately fails. The trailing exit determines how long we remain aboard if it succeeds.
The market eventually tells us what we caught.
Not the entry.
“The entry does not know what it has detected. It knows only that the condition has been met. That is enough.”
Two Very Different Things Can Cross the Same Threshold
Not every trend is the same.
This distinction matters enormously.
Most directional moves are relatively ordinary. They occur within an existing regime, travel for a while and eventually exhaust themselves. I think of these as convergent trends. They remain, in some meaningful sense, connected to the structure from which they emerged.
Then there are the others.
The rare ones.
The moves that accompany a genuine change in the underlying regime. Price does not merely travel within the old structure. The structure itself is changing.
These are outlier trends.
The 2022 bond repricing. Cocoa in 2023 and 2024. Violent currency dislocations. The great commodity moves that appear periodically throughout market history.
These are the events the Outlier Hunter is built to find.
The problem is beautifully simple.
At the beginning, we do not know which kind we are looking at.
A breakout that ultimately travels three ATR and reverses may initially cross precisely the same threshold as one that travels thirty ATR.
There is no little flag on the chart saying:
THIS ONE IS THE OUTLIER.
If there were, everyone would trade it.
So we accept something that feels deeply uncomfortable to anyone raised on conventional ideas about trading accuracy.
We accept false signals.
Lots of them.
We accept small losses.
Lots of them too.
Because the alternative is to demand so much evidence that by the time the extraordinary event has identified itself, we are standing on the platform watching it disappear into the distance.
This is why win rate tells us remarkably little about the quality of an Outlier Hunter’s entry logic.
The objective is not to make every entry right.
The objective is to make sure the system is capable of being present when one of the rare, consequential moves begins.
The small losses are not evidence that the mechanism is malfunctioning.
They are the admission price.
Why Simplicity Matters
Once you understand that an entry mechanism will generate false signals, the temptation is obvious.
Fix them.
Add a confirmation rule.
Then another.
Perhaps a momentum filter. A volatility filter. A regime classifier. Something to identify when breakouts are statistically more likely to succeed.
Backtests can reward this handsomely.
That is precisely where the danger begins.
Every additional condition embeds another proposition about how the market behaves. The more conditions we add, the more specific the system becomes to the historical environments in which those conditions were discovered and calibrated.
But markets do not owe us repetition.
They change.
Participants change.
Liquidity changes.
Policy changes.
Technology changes.
The strategies being used by other participants change.
The next great trend does not have to resemble the last one.
A filter that successfully eliminated yesterday’s false breakouts may also eliminate tomorrow’s first genuine breakout because, at its birth, the new regime may look exactly like the noise the filter was designed to suppress.
This is why I have such a strong preference for simple rules.
Not because simple rules are magically superior.
Not because they avoid losses.
They don’t.
Simple rules can look positively stupid for long stretches of time.
That is part of their strength.
A Donchian breakout in a directionless market may repeatedly enter, get stopped out and enter again. It looks unsophisticated because it is unsophisticated. It has no opinion about what the market should be doing.
Then the environment changes.
The next threshold is crossed.
And the same dumb rule fires.
It does not need to recognise the regime transition. It does not need to understand why it happened. It does not need to decide whether this time is different.
It is already there.
Complexity often buys historical precision at the cost of future adaptability.
Simplicity gives up that precision in exchange for something I value much more:
fewer assumptions about a future we cannot know.
“A simple rule applied consistently for twenty years will outlive a clever rule that requires the market to cooperate.”
The Entry Does Not Stand Alone
There is another mistake we make when discussing entries.
We isolate them.
We talk about an entry rule as though it were an independent trading decision.
It isn’t.
The moment an entry fires, it becomes part of an integrated structure.
Suppose the system uses ATR to scale the initial stop. A market moving violently from day to day requires a wider price stop than a quiet market. That same distance feeds into position sizing. A wider stop means fewer contracts. A narrower stop permits more.
So the sequence is not really:
Entry. Stop. Position size.
These are not three unrelated decisions.
They are connected pieces of the same calculation.
The entry establishes the price at which exposure begins. The stop establishes the intended distance at which the initial thesis is abandoned. Position sizing converts that distance into an amount of exposure consistent with the programme’s capital allocation rules.
This is how very different markets can coexist inside the same portfolio.
A bond future, a currency, cocoa and an equity index may have completely different prices, contract specifications and day-to-day movement. The system does not need them to behave alike.
It needs a consistent way to translate their differences into comparable units of exposure.
This is where entry logic stops being merely a signal and becomes part of the machinery of portfolio construction.
Before the Entry, There Is the Data
There is an even earlier dependency that is easy to overlook.
The entry signal fires on a price series.
So what exactly is that price series?
For futures traders, this is not a trivial question.
Futures contracts expire. A long-term systematic programme therefore needs some method of constructing a continuous historical series across successive contracts. How those contracts are joined and adjusted affects the historical price path on which indicators, breakouts, ATR calculations and research are based.
That means a beautifully designed entry rule running on poorly constructed or inconsistent data is not a robust entry rule at all.
The system only sees the world through the data we give it.
Change the lens and, in some circumstances, you change the signal.
We will return to this in Episode 6 when we pull apart rollover mechanics. For now, the important point is simply this:
Entry logic begins before the entry rule.
It begins with the integrity of the information presented to it.
One Entry Rule Is Not the Programme
Now we can widen the lens.
A single entry rule applied to a single market gives us one particular way of encountering trends.
But trends do not announce themselves in one particular way.
Some creep.
Some explode.
Some emerge from long compression.
Some grind gradually until, almost without anyone noticing, the market has travelled an extraordinary distance.
This is why the programme uses an ensemble.
Different entry mechanisms respond to different features of price behaviour. A channel breakout reacts when price escapes a defined range. A moving-average crossover responds to a change in directional structure across different time horizons. A volatility-envelope system responds when price moves sufficiently far from a central reference.
They do not all enter on the same day.
Good.
That is the point.
No single entry mechanism needs to be the universal detector of trends because no such detector exists.
Instead, we allow several simple mechanisms to observe the market from slightly different angles.
A slow-developing trend may attract one system first.
An explosive breakout may trigger another.
As the move develops, others may join.
What matters is not that every system identifies every trend at the perfect moment. What matters is that the architecture gives the programme multiple opportunities to participate in the broad distribution of trending behaviour.
Diversity does something here that additional complexity inside a single entry rule cannot.
Rather than asking one mechanism to become cleverer, we allow several simple mechanisms to remain different.
That distinction runs through almost everything I believe about robust systematic trading.
What the Entry Is Not Responsible For
This brings us to perhaps the cleanest way to understand entry logic.
Look at everything it does not have to do.
It does not have to produce a high win rate.
It does not have to know whether the move it has detected will continue.
It does not have to maximise the size of the winner. That belongs largely to the exit.
It does not have to ensure the programme survives a long sequence of losses. That belongs to position sizing, portfolio construction and the defensive machinery of the programme, including the Cut Back Rule.
It does not have to identify the next great market.
Diversification handles that problem.
And it certainly does not have to predict the future.
Its job is much smaller.
When the condition is met, enter.
That simplicity is deceptive because we instinctively want the entry to know more.
We want certainty.
We want confirmation.
We want the system to tell us that this time the breakout is real.
But the entire architecture exists because that knowledge is unavailable when it matters most.
Some entries will fail almost immediately.
Others will travel a little way and come back.
Occasionally, one will keep going.
And going.
And going.
At the moment of entry, they may all have looked much the same.
That is not a failure of the system.
That is the reason the rest of the system exists.
The entry opens the door without knowing what is on the other side.
The stop limits what we can lose if there is nothing there.
Position sizing makes repeated mistakes survivable.
The exit gives the extraordinary trade room to become extraordinary.
Diversification increases the number of places in which we can find it.
The ensemble increases the number of ways in which we can encounter it.
No component possesses certainty.
No component needs to.
The intelligence is in the architecture.
And that is where we go next.
Because once the entry has opened the door, the most important question in trend following is no longer how we got in.
It is what makes us get out.
READ DEEPER
→ Your Trend is Different to My Trend
→ The Birth of Trends: The Counterintuitive Role of Noise
→ Trend Is Structural, Not an Inefficiency: Why It Cannot Be Arbitraged Away
→ The Paradox of Simplicity: Why the Best Trading Rules Are Counterintuitive
→ Selection, Not Skill: Why Simple Strategies Outlive Brilliant Ones
Previous: Introduction: The Programme, From the Inside | Next: System Anatomy 2: Exit Logic
Richard Brennan writes on systematic trading, complex adaptive markets, and the philosophical foundations of trend following at atstradingsolutions.com. His books include The Fractals of Finance, Complex Adaptive Markets, Carved by Impossibility and The Aussie Turtles Trend Following Guide.
Want to explore why structure exists at all?
Carved by Impossibility: What Remains When Everything Else Is Eliminated
The book explores the architecture of constraint, emergence, and reality itself, and what it means for how we understand markets, life, and the universe.
Available now on Amazon in paperback, hardcover, and Kindle.
Want the theoretical foundation for why trend following works?
The Fractals of Finance: Determinism, Adaptation and the Geometry of Markets
The book explores the full architecture of feedback, fat tails, and fractal structure in financial markets, and what it means for how we trade, invest, and understand risk.
Available now on Amazon in paperback, hardcover, and Kindle.
Want a practical field manual for trading trends and capturing outliers?
The Aussie Turtles Trend Following Guide: A Field Manual for Hunting Outliers adapts the timeless principles of the original Turtle traders into a systematic, rules-based approach for modern markets. Co-authored with Adam Havryliv.
Available now on Amazon in paperback, hardcover, and Kindle.