You’re watching a stock climb. It pulls back, then pushes higher again. Classic uptrend—so you buy the dip. Ten minutes later, the stock reverses hard and stops you out. Then it bounces right back up to where it was before.
What happened? The stock wasn’t trending. It was stuck in a range. And you just applied a trend-following strategy to a range-bound market.
This is one of the most expensive mistakes in day trading, and almost every beginner makes it. Not because they chose the wrong indicator or the wrong stock—but because they never asked the most fundamental question before entering a trade: Is this market trending or ranging right now?
That question—and knowing how to answer it in seconds—is what separates traders who adapt from traders who get chopped up. Our team considers this the single most important diagnostic skill a day trader can develop. Everything else—your strategy, your entries, your exits—flows from this one read.
What Is a Trending Market?
A trending market is one where price is moving in a clear, sustained direction—either up or down. That’s it. No mystery. But the key word is sustained. A stock that pops 3% on news and immediately gives it back isn’t trending. A stock that grinds higher over 30 minutes, making a series of progressively higher peaks and higher valleys? That’s a trend.
Here’s the technical definition you’ll see everywhere: an uptrend is a series of higher highs and higher lows. Each time price pulls back, it doesn’t fall as far as the last pullback. Each time it rallies, it pushes past the previous peak. Imagine climbing a staircase—each step takes you higher than the last.
A downtrend is the mirror image: lower highs and lower lows. Each rally fails to reach the previous peak, and each drop pushes to a new low. The staircase is descending.
Why do trends form? They happen when there’s a persistent imbalance between buyers and sellers. In an uptrend, demand consistently outweighs supply—more traders want to buy than sell at current prices, so the price keeps getting bid up. In a downtrend, supply overwhelms demand. Sellers are in control, and buyers aren’t willing to step in until prices fall further.
Trends can last minutes on a 1-minute chart or hours on a 5-minute chart. For day traders, even a 20-minute trend on an intraday stock can offer a solid trade. The important thing isn’t how long the trend lasts—it’s recognizing that one exists before you put money on the line.
One thing that trips up new traders: trends don’t move in straight lines. Even the strongest uptrend will have pullbacks—brief dips where sellers take some profit or buyers pause. These pullbacks are normal. They’re actually what create the “higher lows” pattern that defines the trend. If price pulled back and never bounced, the trend would be over.
What Is a Range-Bound Market?
A range-bound market—also called a sideways market, a consolidation, or a choppy market—is the opposite of a trend. Price bounces back and forth between two rough levels without making meaningful progress in either direction.
Think of it like a tennis ball bouncing between the floor and the ceiling. The floor is support—a price level where buyers consistently step in and prevent further decline. The ceiling is resistance—a level where sellers show up and cap the rally. Price hits resistance, drops. Hits support, bounces. Over and over.
For a deeper breakdown of how these levels work, check out our guide to support and resistance.
Here’s the part most beginners don’t realize: markets spend the majority of their time in ranges, not trends. Various estimates put the split at roughly 60–70% ranging and only 30–40% trending. Some analysts and professional traders cite the 80/20 rule—suggesting markets trend meaningfully only about 20–25% of the time.
That statistic alone should change how you think about trading. If you only know trend-following strategies, you’re equipped for maybe a third of market conditions. The rest of the time? You’re either sitting on your hands—which is fine, by the way—or getting eaten alive trying to force trend trades in a choppy market.
Ranges form when buyers and sellers reach a temporary equilibrium. Neither side has enough conviction to push price decisively higher or lower. This often happens during periods of uncertainty—before a major economic report, between news catalysts, or after a big move when the market needs to “digest” what just happened. It’s the market catching its breath.
Why Identifying Market Conditions Is the Most Important Skill You’ll Learn
Here’s a statement that might sound dramatic but is absolutely true: every strategy you’ll ever learn works in some market conditions and fails in others. There is no universal strategy. There is no indicator that works all the time. The variable that determines whether your approach prints money or bleeds money is the condition of the market you’re applying it to.
Trend-following strategies—buying pullbacks in uptrends, riding momentum, following moving average crossovers—work beautifully when the market is actually trending. Apply those same strategies in a range? You’ll buy near resistance and sell near support. You’ll chase breakouts that immediately reverse. You’ll get whipsawed over and over.
Range-trading strategies—fading moves at support and resistance, mean reversion, selling overbought readings—work well in sideways markets. Apply them during a real trend? You’ll fade a move that keeps going. You’ll short a stock that’s breaking out to new highs. You’ll catch a falling knife in a downtrend.
Neither strategy is “wrong.” They’re just designed for different environments. The skill—the real, foundational skill—is reading which environment you’re in before you deploy your playbook.
Our team has seen this pattern destroy more beginner accounts than almost any other mistake. A new trader learns a breakout strategy, and it works a few times during a trending week. Then the market goes sideways, and they keep applying the same strategy. Breakout after breakout fails. They lose confidence, question the strategy, maybe abandon it entirely—when the real problem was never the strategy. It was applying it in the wrong conditions.
Once you internalize this, trading gets simpler. Not easy—simpler. You stop asking “What should I trade?” and start asking “What is the market doing right now, and which playbook fits?”
How to Tell If a Market Is Trending or Ranging: The 3-Question Diagnostic
This is the practical core of this article. Our team uses a quick three-question framework that you can apply to any chart in about 10 seconds. You don’t need fancy tools. You don’t need proprietary indicators. You need your eyes and maybe one or two basic overlays.
Question 1: Is Price Making Higher Highs and Higher Lows (or Lower Highs and Lower Lows)?
This is pure price action—no indicators required. Look at the last several swings on your chart.
A swing high is a short-term peak where price reversed and started dropping. A swing low is a short-term trough where price reversed and started climbing. You can usually spot these by eye once you know what to look for.
If each swing high is higher than the last, and each swing low is higher than the last—you’re in an uptrend. If each swing high is lower, and each swing low is lower—downtrend. If the highs and lows are roughly equal, bouncing between the same levels—range.
This sounds simple. It is simple. And it’s the single most reliable read you can make. No indicator will ever beat price structure for telling you what the market is doing.
The catch? It gets messy in real time. Sometimes a swing low dips slightly below the previous one, but the overall structure still looks bullish. Sometimes you see one higher high but the lows are flat. These gray areas are where questions 2 and 3 help.
Question 2: What Are the Moving Averages Doing?
Overlay a short-term moving average—a 9 EMA or 20 EMA works well for day trading timeframes—on your chart. For a deeper dive on moving averages and when to use EMAs versus SMAs, see our Moving Averages guide.
Now ask:
- Is the MA sloping clearly upward or downward? That suggests a trend.
- Is the MA flat or barely moving? That suggests a range.
- Is price staying consistently above the MA (uptrend) or below it (downtrend)? Or is price criss-crossing the MA repeatedly? Constant crossovers = choppy, range-bound action.
When a market is trending, moving averages act like a trail behind the price—following along, providing dynamic support or resistance. When a market is ranging, moving averages flatten out and become useless. Price chops through them from both sides, generating nothing but false signals.
You can take this a step further by watching two moving averages—say, the 9 EMA and the 20 EMA. In a trend, they separate and “fan out,” with the faster one (9 EMA) pulling away from the slower one (20 EMA). In a range, they converge, flatten, and start overlapping. The degree of separation between your MAs is a quick visual proxy for trend strength.
Question 3: How Strong Is the Directional Move? (The ADX Shortcut)
The Average Directional Index (ADX) is a tool built specifically for this question. Developed by J. Welles Wilder in 1978, the ADX measures how strong a trend is on a scale from 0 to 100—without telling you the direction. It doesn’t care if the market is going up or down. It only measures how much directional conviction exists.
The key thresholds most traders use:
- ADX below 20: Weak or absent trend. The market is likely range-bound. Trend-following strategies will get chopped up here.
- ADX between 20 and 25: The gray zone. A trend might be forming, but it’s not confirmed yet. Watch closely but don’t commit to trend trades.
- ADX above 25: A legitimate trend with real strength behind it. This is where trend strategies have a meaningful edge.
- ADX above 50: Very strong trend—but possibly approaching exhaustion. The move is powerful, but you might be late.
Here’s the practical application: don’t use trend-following strategies when the ADX is below 20. Just don’t. It’s the single most effective filter you can add to your trading. When ADX is below 20, either trade the range (buy support, sell resistance) or sit out entirely. When ADX climbs above 25, you’ve got confirmation that directional strategies are appropriate.
One important nuance: the ADX is a lagging indicator. By the time it crosses above 25, a trend has already been underway for a while. That’s okay. You’re not trying to catch the absolute beginning of a trend—you’re trying to avoid getting chopped up in a range. The ADX won’t make you early, but it’ll keep you from being wrong.
Putting the Diagnostic Together
Run through all three questions quickly:
Scenario A: Price is making higher highs and higher lows. The 20 EMA is sloping upward and price is staying above it. ADX is at 32 and rising. Verdict: Trending. Look for pullback entries, ride momentum, trail your stops.
Scenario B: Price keeps bouncing between $45.50 and $46.20. The 20 EMA is flat. ADX is at 15. Verdict: Range-bound. Either fade the extremes (buy near $45.50, sell near $46.20) or wait for a breakout with ADX confirmation.
Scenario C: Price broke above yesterday’s high, but the ADX is still at 18, and the 20 EMA hasn’t started sloping. Verdict: Unconfirmed breakout. Proceed with caution—this could be a fake move that reverses right back into the range.
Ten seconds. Three questions. That’s all it takes to diagnose market conditions before you risk a dollar.
The Tools That Help: Moving Averages and ADX
We’ve already touched on the key tools above, but let’s consolidate the practical toolkit.
For identifying trends:
- 9 EMA and 20 EMA on your intraday chart (1-minute or 5-minute). Watch the slope and separation. Trending markets show fanning MAs with price riding above (uptrend) or below (downtrend).
- ADX (14-period, standard setting). Above 25 = trend confirmed. Below 20 = range likely.
- Your eyes. Seriously. Before you check any indicator, look at the raw price action. Higher highs/lows? Lower highs/lows? Flat? Your brain can process price structure faster than any indicator can calculate it.
For identifying ranges:
- Horizontal support and resistance lines. If you can draw two horizontal lines that price keeps bouncing between, you’ve found a range. The more times price tests these levels, the more valid the range is.
- Flat moving averages. When the 20 EMA goes sideways and price chops through it repeatedly, the market is directionless.
- ADX below 20. This is your “stay away from trend strategies” signal.
A quality charting platform makes all of this easier. Whether you’re using TradingView, a broker’s built-in charts, or a dedicated platform, you want one that lets you quickly overlay MAs and the ADX. We compare the top options in our Day Trading Toolkit.
For finding stocks that are already trending with strong momentum—so you don’t have to manually scan dozens of charts—a real-time scanner is invaluable. Trade Ideas lets you filter for stocks with high relative volume, price above key moving averages, and strong directional movement, essentially doing the diagnostic for you across the entire market simultaneously.
What to Do in a Trending Market vs. a Ranging Market
Diagnosing the condition is step one. Step two is knowing which playbook to open.
In a Trending Market: Go With the Flow
The golden rule of trend trading is simple: trade in the direction of the trend. Don’t fight it. Don’t try to call the top or bottom. The trend exists because one side—buyers or sellers—is clearly dominant. You want to be on that side.
Practical actions:
- Buy pullbacks in uptrends. Wait for price to dip toward the 9 or 20 EMA, then enter when it shows signs of bouncing. Your stop goes below the most recent swing low. We cover this approach in detail in our Pullback Trading Basics guide.
- Sell rallies in downtrends (if you’re experienced enough to short). Wait for a bounce into a moving average or former support-turned-resistance, then enter short.
- Trail your stop-loss. Trends can run much further than you expect. Don’t cap your upside with a rigid target. Instead, trail your stop behind each new swing low (in an uptrend) to let the trade breathe. For more on trailing stops, see our Trailing Stops & Bracket Orders guide.
- Don’t fight the direction. If the trend is up, don’t short. If the trend is down, don’t try to “buy the bottom.” The trend is your informational edge—respect it.
In a Ranging Market: Fade the Edges or Sit Out
Range-bound markets reward a completely different mindset. Instead of following momentum, you’re betting on mean reversion—the idea that price will return to the middle of the range after hitting an extreme.
Practical actions:
- Buy near support, sell near resistance. This is the textbook range trade. When price drops to the bottom of the range and shows signs of bouncing, you buy. When it rallies to the top and stalls, you sell. Your targets are modest—you’re aiming for the other side of the range, not a breakout.
- Keep position sizes smaller. Ranges are inherently uncertain. The range could break at any moment, and your “support” buy could turn into a breakout-to-the-downside nightmare. Tighter risk.
- Use oscillators for timing. Indicators like RSI tend to work well in ranges because they measure overbought/oversold conditions—which are actually meaningful when price is bouncing between two levels. For more on these tools, check our RSI, MACD & Bollinger Bands guide.
- Consider sitting out entirely. This is a legitimate and often optimal choice. If you primarily trade breakouts or momentum, a range-bound day offers nothing for you. Walking away when conditions don’t match your strategy isn’t weakness—it’s discipline. We’ve written about this in our guide on When to Sit Out.
Here’s a reality check: many professional day traders actually avoid range-bound stocks entirely. They use scanners to find the handful of stocks that are trending on any given day, even when the broader market is flat. Markets might range 70% of the time on average, but there are almost always individual stocks trending somewhere. You just have to find them.
The Transition Zone: When Ranges Break Into Trends (and Vice Versa)
Markets don’t stay in one state forever. Ranges eventually break. Trends eventually exhaust. The transition between these states is where some of the biggest opportunities—and biggest traps—live.
From Range to Trend: The Breakout
A breakout happens when price pushes through the support or resistance level that has been containing the range. If price breaks above resistance with conviction, it can signal the start of a new uptrend. If it breaks below support, a potential downtrend.
The problem? Most breakouts fail. This is especially true in low-conviction environments where the ADX is still weak. Price pokes above resistance, triggers a bunch of buy orders, then reverses and drops back into the range. These “fake breakouts” or “fakeouts” are the bane of breakout traders.
How to tell a real breakout from a fake one:
- Check the ADX. If ADX is rising and crossing above 25 as the breakout happens, the move has genuine momentum behind it. If ADX is flat at 15, be skeptical.
- Watch volume. Real breakouts tend to come with a surge in volume—a sign that serious money is behind the move. A breakout on low volume is suspicious.
- Wait for confirmation. Instead of buying the instant price crosses resistance, wait to see if it holds above the level. A close above resistance (on a 5-minute candle, for example) is more meaningful than a quick wick above it.
We have a full breakdown of this in our Breakout Trading Basics guide.
From Trend to Range: The Exhaustion
Trends don’t end with a dramatic reversal every time. Often, they just… fizzle. Price stops making new highs. Pullbacks get deeper. The ADX peaks and starts declining. Moving averages flatten. Gradually, the trend morphs into a range.
Recognizing this shift prevents you from stubbornly holding a trend trade that’s no longer trending. Watch for:
- ADX peaking above 40-50, then turning downward. This is the trend losing steam—even if price hasn’t reversed yet.
- Moving averages converging. The 9 and 20 EMAs start overlapping instead of fanning apart.
- Swing structure breaking down. In an uptrend, the first sign of trouble is when price makes a lower low—it fails to hold the previous pullback level. That doesn’t mean the trend is dead, but it’s a yellow flag.
When you see these signals, tighten your stops, take partial profits, and prepare to shift your approach.
The #1 Beginner Mistake: Using the Wrong Strategy for the Wrong Market
We’ve hinted at this throughout, but it deserves its own section because it’s that common.
The mistake is straightforward: a beginner learns one strategy—say, breakout trading—and applies it in every market condition. During trending days, they do well. During range-bound days (which are more frequent), they get destroyed. They think the strategy is broken. They switch to a new strategy. The cycle repeats.
The real problem was never the strategy. It was the failure to diagnose the market condition first.
Here’s a quick mental model that might help. Think of your trading strategies as shoes. Running shoes are great—for running. But you wouldn’t wear them to a formal dinner, and you wouldn’t wear dress shoes on a trail run. Neither pair is “wrong.” They’re designed for different conditions. Your job as a trader is to look at the terrain first, then pick the right shoes.
Another version of this mistake is more subtle: seeing trends that aren’t there. A stock gaps up 2% at the open, and a beginner assumes it’s going to trend all day. But after the initial push, it settles into a range. The gap up was the event. The range is the aftermath. Mistaking a single move for a trend leads to chasing, FOMO, and buying high.
Real trends show sustained price structure—multiple swings, consistent direction, confirmed by your diagnostic questions. One move isn’t a trend. It’s a move.
The fix is surprisingly simple: before every trade, run the 3-question diagnostic. Is price making consistent highs/lows? What are the MAs doing? What’s the ADX reading? If the answers don’t match the strategy you’re about to use, either switch strategies or don’t trade.
That one habit—diagnosing before trading—will save you more money than any indicator ever will.
What’s Next in Your Day Trading Journey
Now that you can read whether the market is trending or ranging, the next step is learning how to test whether a strategy actually works before you risk real money on it. That’s where backtesting comes in—a way to apply your strategy to historical data and see if it would have been profitable.
→ Next Article: How to Backtest a Strategy Without Code: A Beginner’s Approach
Frequently Asked Questions
What is the difference between a trending market and a ranging market?
Quick Answer: A trending market moves in a sustained direction (up or down) with higher highs/lows or lower highs/lows. A ranging market moves sideways between support and resistance without making directional progress.
The core difference comes down to directional conviction. In a trend, one side—buyers or sellers—is consistently dominant, pushing price in their direction with each new swing. In a range, buying and selling pressure are roughly balanced. Price bounces between two levels like a pinball. The distinction matters because the strategies that profit in one condition tend to lose in the other.
Key Takeaway: Always identify whether the market is trending or ranging before choosing a strategy—it’s the most important diagnostic step in day trading.
How much time does the market spend in a range versus a trend?
Quick Answer: Most estimates suggest markets spend 60–70% of the time in ranges and only 30–40% of the time in clear trends. Some analysts cite an even wider 80/20 split.
The exact ratio varies by market, timeframe, and how strictly you define “trending.” But the direction is consistent: ranging conditions are far more common. This has a practical implication—if you only know trend-following strategies, you’re equipped for the minority of trading conditions. Learning to either trade ranges or recognize when to sit out is essential for long-term survival.
Key Takeaway: Ranges are the norm, not the exception. Building a skill set for sideways markets—or the discipline to sit them out—is critical.
What is the ADX indicator and how does it help identify trends?
Quick Answer: The ADX (Average Directional Index) measures trend strength on a 0–100 scale. Readings above 25 suggest a strong trend; below 20 indicates a ranging or trendless market.
Created by J. Welles Wilder in 1978, the ADX doesn’t tell you whether the trend is up or down—only how strong the directional movement is. The standard interpretation uses 14-period settings. The most important threshold is 25: many professional traders refuse to take trend-based trades when ADX is below that level. One limitation to know: ADX is a lagging indicator, so it confirms trends rather than predicting them.
Key Takeaway: Use ADX as a filter—don’t apply trend strategies when ADX is below 20, and gain confidence in trend trades when it’s above 25.
Can a stock be trending on one timeframe but ranging on another?
Quick Answer: Absolutely. A stock might be in a clear uptrend on the daily chart while ranging on the 5-minute chart, or vice versa. This is why multi-timeframe awareness matters.
Day traders typically make decisions on shorter timeframes (1-minute, 5-minute), but the higher timeframe context shapes the environment. If the daily chart shows a strong downtrend, a range on the 5-minute chart might resolve with a breakdown rather than a breakout. Checking at least one higher timeframe before trading helps avoid surprises. For more on this, see our Multi-Timeframe Analysis guide.
Key Takeaway: Always check at least one higher timeframe to understand the broader context before trading shorter-term conditions.
What’s the best indicator for identifying trend vs. range?
Quick Answer: There’s no single “best” indicator—but the combination of price action (higher highs/lows), moving average slope, and ADX gives you the most reliable read.
Price action is the foundation. No indicator processes information faster than your eyes scanning swing structure. Moving averages add a quick visual overlay: sloping and separated = trend; flat and overlapping = range. ADX provides a numerical threshold. Together, these three form a diagnostic that takes about 10 seconds and covers the key bases. Oscillators like RSI can complement in ranges but tend to give misleading signals during trends.
Key Takeaway: Lead with price action, confirm with MAs, and use ADX as your final filter. No single indicator does it all.
Why do breakouts from ranges fail so often?
Quick Answer: Most breakouts fail because there isn’t enough genuine buying or selling conviction behind the move—price pokes past a level, triggers orders, then reverses back into the range.
False breakouts are one of the most frustrating patterns in trading, and they happen frequently in low-ADX environments. Market makers and algorithmic traders sometimes push price through a level specifically to trigger stop-loss orders and attract breakout buyers, then reverse the move. The best defense is confirming breakouts with volume surges, ADX rising above 25, and waiting for price to hold beyond the level rather than just touch it.
Key Takeaway: Don’t chase every breakout. Wait for confirmation from volume and ADX before committing capital.
Should beginners trade ranges or just focus on trends?
Quick Answer: Most beginners should focus on trending markets first. Trends offer clearer signals, simpler decision-making, and better risk/reward. Range trading requires more precision and faster reflexes.
Trend trading is more forgiving for beginners because the directional bias gives you a built-in edge—you’re swimming with the current, not against it. In ranges, you’re making bets on reversals at specific price levels, which demands tighter execution and more experience reading price action at support and resistance. Start by learning to identify trends, trade them, and sit out when the market is ranging. Add range strategies later as your skill grows.
Key Takeaway: Master trend identification and trend-following first. Sitting out range-bound conditions is better than forcing trades you’re not ready for.
How do I know when a trend is ending?
Quick Answer: Watch for the ADX peaking and declining, moving averages converging, and the swing structure breaking down (e.g., an uptrend making its first lower low).
Trends rarely end with a single dramatic reversal. More often, they gradually lose steam. The ADX might peak at 45 and start sliding back toward 25. Moving averages that were fanning apart begin overlapping. Price makes a new high but barely surpasses the last one, then the next pullback drops deeper than previous pullbacks. These are warning signs—not guarantees—that the trend is transitioning into a range or potential reversal.
Key Takeaway: When ADX declines from a peak and swing structure weakens, tighten your stops and prepare to shift your approach.
What is mean reversion and why does it matter in ranges?
Quick Answer: Mean reversion is the tendency for price to return to its average after moving to an extreme. In range-bound markets, this principle underlies the strategy of buying at support and selling at resistance.
When a market is ranging, price is essentially oscillating around a “fair value” area—the middle of the range. Each push to support or resistance represents a temporary extreme that tends to snap back. Indicators like VWAP—which we cover in our VWAP guide—and Bollinger Bands help measure these extremes. Mean reversion strategies work well in ranges but get destroyed in trends, because when a trend takes hold, price doesn’t revert to the mean—it keeps moving away from it.
Key Takeaway: Mean reversion works in ranges, not trends. Always confirm the market condition before applying a reversion strategy.
Is the overall market (SPY/QQQ) trending or ranging most of the time?
Quick Answer: The broad market indices spend more time in ranges than trends, but individual stocks can trend even on days when the indices are flat.
On any given day, SPY or QQQ might be stuck in a 0.3% range. But within that “quiet” market, individual stocks—driven by earnings, news, or unusual volume—can move 5%, 10%, or more with strong trends. This is why stock selection is so powerful for day traders. You don’t need the whole market to trend. You need to find the individual names that are trending today. A real-time scanner helps enormously here—we break down the top options in our Day Trading Toolkit.
Key Takeaway: Don’t wait for the broad market to trend. Find individual stocks that are trending, even when the indices are sideways.
Disclaimer
The information provided in this article is for educational purposes only and should not be considered financial advice. Day trading involves substantial risk and is not suitable for every investor. Past performance is not indicative of future results.
For our complete disclaimer, please visit: https://daytradingtoolkit.com/disclaimer/
Article Sources
Our team built this article on research from leading financial education platforms and the foundational technical analysis work of J. Welles Wilder. These sources provide additional depth on market structure, trend identification, and the ADX indicator system.
- Investopedia — Average Directional Index (ADX) — Comprehensive overview of the ADX indicator, including interpretation thresholds and practical trading applications.
- Corporate Finance Institute — ADX Indicator Technical Analysis — Detailed explanation of how ADX distinguishes trending from range-bound markets, with chart examples.
- Fidelity — Average Directional Index (ADX) — Practical interpretation of ADX readings with current market context from one of the largest U.S. brokerages.
- StockCharts ChartSchool — Average Directional Index (ADX) — Technical breakdown of ADX calculation, directional movement components, and signal interpretation.
- CME Group — Introduction to Technical Analysis — Exchange-level educational material on market trends, price structure, and technical indicator fundamentals.
- Wilder, J. Welles. New Concepts in Technical Trading Systems (1978). Trend Research. — The original source for the ADX indicator and the Directional Movement System, still considered foundational technical analysis literature.



