Base hits or home runs? Test your edge without P&L outliers
Trimming P&L outliers explained: remove your biggest winners and losers, recalculate expectancy, and find out if your trading edge is a process or luck.
To test whether your trading edge is real, remove the same small share of your biggest winners and biggest losers - say the top and bottom 5% - and recalculate your statistics on what’s left. If expectancy stays positive, your results come from a repeatable process: base hits. If it disappears, you’re relying on a few home runs.
Line up every trade you took last month by P&L and you’ll get something close to a bell curve. Most trades sit in the middle - small wins, small losses, scratches. A few sit far out on the tails: the trade that ran all day, and the one where you moved your stop.
Those tails can tell you more about your trading than the average ever will.
This guide shows how to trim outliers from your results, how to read what’s left, and why the trades themselves should stay in your journal.
Key takeaways
- Same P&L can hide very different processes. A month built on base hits is repeatable; a month rescued by one home run is not.
- Trim both tails equally - for example the top and bottom 5% of trades - then recalculate.
- Edge holds: your process is real and can be sized up.
- Edge disappears: you depend on home runs; work on the middle of the distribution.
- Edge improves: a few blow-ups are erasing a good process; tighten your stop discipline.
- Don’t delete outliers. Set them aside in a view you can switch on and off.
Two traders, same month
Imagine two traders who both finished the month up $3,000.
The first made it in steady increments: lots of modest winners, losses kept small, no single trade bigger than $400.
The second was down $1,500 going into the last week, then caught one trend day for $4,500.
Same P&L, completely different businesses. The first trader has a process - something repeatable that can be refined and sized up. The second has a process that loses money, rescued by a home run. Next month, if the home run doesn’t come, the result looks very different.
How to trim outliers and recalculate
The test is simple. Remove a small percentage of your biggest winners and your biggest losers - say the top and bottom 5% of each - and recalculate your statistics on what’s left. Expectancy is the one to watch: it’s your average profit or loss per trade.
What the result tells you
Then read the result:
- Your edge holds. Expectancy stays positive without the tails. Your results come from base hits - a process you can trust and scale.
- Your edge disappears. You’re relying on home runs. That’s a fragile way to trade: one missed runner and the month goes red. Work on the middle of the distribution.
- Your edge improves. A few blow-ups are erasing a good process. The fix isn’t your strategy - it’s your stop discipline. Find what those trades have in common.
| After trimming the tails | What it means | What to work on |
|---|---|---|
| Edge holds | Your results come from base hits | Trust the process and scale it |
| Edge disappears | You rely on home runs | The middle of the distribution |
| Edge improves | Blow-ups erase a good process | Stop discipline |
If blow-ups are the problem, MFE and MAE can show how far those trades went against you - and whether they went your way first.
Why trim both winners and losers?
Trimming both sides matters. Removing only your best trades makes everyone look worse; removing only your worst makes everyone look better. Taking the same share from each tail shows you the shape of your everyday trading.
Should you delete outlier trades?
No. The outliers are real money and real lessons, so they belong in your journal. What you want is a view that sets them aside - a lens you can switch on and off - not a spreadsheet where you delete rows and hope you remember to put them back.
How Premo helps
In Premo Trading, outlier exclusion is a setting: choose a percentage and the top and bottom share of your winners and losers are left out of every statistic while it’s on. Nothing is deleted. Pair it with P&L filters - above, below or between any amount - to study exactly the trades you care about. See how it works in the Trade Journal.
This article is educational and is not investment advice. Trading involves substantial risk of loss.
Frequently asked questions
What is an outlier trade?
An outlier trade sits far out on either tail of your P&L distribution: one of your biggest winners, such as a trade that ran all day, or one of your biggest losers, such as a trade where you moved your stop. Most trades sit in the middle - small wins, small losses and scratches.
How do you remove outliers from your trading results?
Remove the same small percentage of your biggest winners and your biggest losers - for example the top and bottom 5% - and recalculate your statistics, such as expectancy, on the trades that are left. Set the trades aside in a view rather than deleting them.
Why trim both winners and losers?
Removing only your best trades makes any trader look worse, and removing only your worst makes any trader look better. Taking the same share from each tail shows the shape of your everyday trading.
What does it mean if my edge disappears without outliers?
It means your results depend on home runs - a few large winners rescuing an otherwise losing process. That is fragile: one missed runner and the month goes red. The work is in the middle of the distribution, on the trades you take every day.
What if my results improve when outliers are removed?
Then a few blow-ups are erasing a good process. The fix is not your strategy but your stop discipline. Look for what those large losing trades have in common.
Should I delete outlier trades from my trading journal?
No. Outliers are real money and real lessons, so they belong in your journal. Use a view that sets them aside while you study the rest - one you can switch on and off - instead of deleting rows.
What does "base hits vs. home runs" mean in trading?
Base hits are the many modest winners and small, controlled losses that make up a repeatable process. Home runs are rare, outsized winners. Two traders can end a month with the same P&L, one built on base hits and one rescued by a single home run, and only the first has a process that can be refined and sized up.