A stock can rise 8% over six weeks and still stop you out three times on the way. The path matters as much as the direction, and the Average Directional Index is the one indicator built to measure the path rather than where it points.
What the ADX measures
J. Welles Wilder created the Directional Movement system and published it in "New Concepts in Technical Trading Systems" in 1978. It contains three lines: the ADX, the Plus Directional Indicator (+DI) and the Minus Directional Indicator (-DI). The ADX defines whether a trend is present and takes no account of direction at all, while +DI and -DI supply the direction (TradingView Help Center).
That split is the whole reason to use it. A rising ADX tells you a move is persistent. It never tells you which way, so a reading of 40 fits a collapse as well as a rally.
Wilder's own levels are on the record: "Wilder believed that a DMI reading above 25 indicated a strong trend, while a reading below 20 indicated a weak or non-existent trend. A reading between those two values, would be considered indeterminable."
The same page adds a caution worth keeping. Wilder developed the system for currencies and commodities, which are typically more volatile than stocks and have stronger trends. The levels that suit the instrument you trade are yours to establish.
The ADX trend strength strategy in rules
This article uses a 14-period ADX on daily bars, with two exponential moving averages for direction. Those are parameters, not findings. Write down the ones you trade.
Filter 1: ADX above 25. Below 20 the rule set stands down. Between 20 and 25 it waits, which is Wilder's indeterminate band rather than a signal to anticipate.
Filter 2: price above the 20-day EMA. Short-term direction. A daily close, not an intraday touch.
Filter 3: price above the 50-day EMA, with the 20-day EMA above the 50-day. Medium-term direction, and the pair in the order a rising trend puts them in.
Wilder's own directional signal is the DI cross, and it is stricter than the EMA pair. The reference sets out the bullish version as a list: ADX over 25, +DI crossing above -DI, and the stop placed at the current day's low. It also states that the signal stands even if -DI later crosses back above +DI, as long as that low is not breached. The last item on its list is that a rising ADX strengthens the signal, and that a trailing stop suits that case. Run either version. Do not blend them and call the result the same strategy.
Exit rules
ADX falls below 20. A drop from 50 to 40 is still a strong reading by Wilder's levels. The exit is the fall through 20, where the reading stops describing a trend at all.
The stop is hit. This article uses 5% below entry. It is a tight stop for a multi-day hold, and it carries a specific consequence: the trade has to work almost immediately or it closes. A wider stop and a smaller position size produce the same dollar risk with more room for ordinary movement.
Whichever you use, the stop is set before the entry and it does not move down afterwards.
Position size and the arithmetic behind it
Risk per trade comes first. Risk 2% of a $50,000 account and the most you lose on the trade is $1,000. With a 5% stop, the position that risks $1,000 is $1,000 / 0.05 = $20,000.
Look at that second number before you use it. A $20,000 position on a $50,000 account is 40% of the account in one stock, and a tight stop is what makes a small dollar risk take up that much capital. An overnight gap through the stop is charged against the position, not against the risk you planned.
The reward side is arithmetic too. A 5% stop with a 3:1 target means a 15% move: 3 x 5% = 15%. Breakeven win rate at 3:1 is 1 / (1 + 3) = 25%. Win 35% of the time at 3R and the average trade is 0.35 x 3R - 0.65 x 1R = +0.40R before costs.
That last figure holds only if your winners reach 3R. The ADX filter does not put them there; it only decides which entries you take.
A hypothetical trade
No real company here, and the prices are chosen to make the arithmetic checkable.
A stock consolidates between $400 and $420 for weeks. It closes at $435, above both the 20-day EMA at $415 and the 50-day at $405, but the ADX reads 22. Under these rules that is not a trade.
Two sessions later the price is $442 and the ADX reads 27. That is the entry.
- Entry: $442.00. Stop: $419.90, which is 5% below. Risk per share: $22.10.
- Target at 3R: $442.00 + 3 x $22.10 = $508.30.
- Risking 2% of a $50,000 account, $1,000 / $22.10 = 45 shares, costing 45 x $442.00 = $19,890.
If the price reaches $508.30, the trade closes at +3R. If the ADX instead falls below 20 while the price sits at $450, the exit rule closes it at whatever the market pays, which is a positive but much smaller R-multiple. Both outcomes come from the rules rather than from a judgment made while the position is open.
Where the ADX strategy goes wrong
Anticipating the level. An ADX of 23 is inside Wilder's indeterminate band. Entering there converts the filter into a preference.
Reading strength as direction. An ADX of 40 with price below the 50-day EMA describes a strong downtrend. The number is the same one a rally produces.
Treating the ADX as an entry timer. It measures the trend that already happened over the lookback period. By the time it crosses 25, part of the move is behind you, which is the cost of waiting for confirmation rather than a flaw to fix.
Running the same levels everywhere. Wilder's 25 and 20 were set for currencies and commodities. If you trade equities, check what the level does to your own trade count before you keep it.
Running the ADX strategy in Swingfolio
A template with this name is in the Strategy Library. On the Strategies page, Import from Library opens the panel; the entry called "ADX Trend Strength" is tagged Trend Following and Intermediate, and it carries 3 entry rules and 2 exit rules. Hover a row and press Preview to see them numbered under Entry Rules (3) and Exit Rules (2), with a Risk Management block showing Stop Loss 5%, Target R-Multiple 3R and Position Size 2%. Import copies it into your strategies, where the numbers become yours to change.
Two screens then answer the question this strategy raises, which is whether you waited for 25.
In the trade form, opening the Pre-Trade Checklist shows the selected strategy's rules with a count badge reading "3 rules". You tick the ones you met. Without a strategy selected, that panel reads "Select a strategy to track rule adherence".
On the strategy's own page, a Rule Adherence card reports Avg Adherence as a percentage over the trades it analysed. Below it, once both groups hold three trades, a Win Rate Comparison sets High Adherence against Low Adherence trades. Under that, a Most Impactful Rules list shows up to three rules' text with the win-rate gap each one made. If the entries where you skipped the ADX filter win less often, that comparison is where it shows up.
Import the template, then tick the checklist honestly on the next 20 entries, including the ones where you jumped in at 23. The Rule Adherence card is only worth reading if the ticks are true. Start the 30-day trial to keep that record in one place.