Plus Directional Indicator (+DI)

The Plus Directional Indicator (+DI) measures the strength of upward price movement in a security. It's a core component of J. Welles Wilder's Directional Movement System and is used alongside the Minus Directional Indicator (-DI) and Average Directional Index (ADX) to identify trend direction and strength.

+DI quantifies bullish pressure by analyzing how much the current high exceeds the previous high, smoothed over a period. Values range from 0 to 100, with higher values indicating stronger upward movement.

Formula

The +DI calculation involves: 1. Calculate +DM (Plus Directional Movement): Max(High - Previous High, 0) 2. Calculate True Range (TR) 3. Smooth +DM and TR over the period 4. +DI = (Smoothed +DM / Smoothed TR) * 100

Parameters

Parameter	Type	Required	Default	Description
high	Array	Yes	-	Array of high prices
low	Array	Yes	-	Array of low prices
close	Array	Yes	-	Array of close prices
period	Integer	No	14	Number of periods for smoothing

Returns

Returns an array of +DI values ranging from 0 to 100. The first period values will be nil.

Usage

require 'sqa/tai'

high =  [48.70, 48.72, 48.90, 48.87, 48.82, 49.05, 49.20, 49.35, 49.92, 50.19, 50.12, 50.10, 50.00, 49.75, 49.80]
low =   [47.79, 48.14, 48.39, 48.37, 48.24, 48.64, 48.94, 49.03, 49.50, 49.87, 49.20, 49.00, 48.90, 49.00, 49.10]
close = [48.20, 48.61, 48.75, 48.63, 48.74, 49.03, 49.07, 49.32, 49.91, 50.13, 49.53, 49.50, 49.25, 49.20, 49.45]

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)

puts "Current +DI: #{plus_di.last.round(2)}"

Interpretation

+DI Value	Upward Movement Strength
0-15	Very weak upward movement
15-25	Weak to moderate upward movement
25-40	Strong upward movement
40-60	Very strong upward movement
60-100	Extremely strong upward movement

Note: Array elements should be ordered from oldest to newest (chronological order)

Key Signals: - +DI > -DI: Uptrend in control, bullish dominance - +DI < -DI: Downtrend in control, bearish dominance - +DI crossover -DI: Bullish signal (uptrend starting) - -DI crossover +DI: Bearish signal (downtrend starting) - Rising +DI: Increasing upward pressure - Falling +DI: Decreasing upward pressure

Example: Trend Direction Identification

high, low, close = load_historical_ohlc('AAPL')

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)
minus_di = SQA::TAI.minus_di(high, low, close, period: 14)

current_plus = plus_di.last
current_minus = minus_di.last

if current_plus > current_minus
  spread = current_plus - current_minus
  puts "UPTREND: +DI (#{current_plus.round(2)}) > -DI (#{current_minus.round(2)})"
  puts "Bullish spread: #{spread.round(2)} points"

  if spread > 20
    puts "Strong uptrend dominance"
  elsif spread > 10
    puts "Moderate uptrend"
  else
    puts "Weak uptrend - watch for reversal"
  end
else
  spread = current_minus - current_plus
  puts "DOWNTREND: -DI (#{current_minus.round(2)}) > +DI (#{current_plus.round(2)})"
  puts "Bearish spread: #{spread.round(2)} points"
end

Example: DI Crossover Strategy

high, low, close = load_historical_ohlc('SPY')

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)
minus_di = SQA::TAI.minus_di(high, low, close, period: 14)

# Current values
current_plus = plus_di.last
current_minus = minus_di.last

# Previous values
prev_plus = plus_di[-2]
prev_minus = minus_di[-2]

# Detect crossovers
if prev_plus < prev_minus && current_plus > current_minus
  puts "BULLISH CROSSOVER DETECTED!"
  puts "+DI crossed above -DI"
  puts "+DI: #{prev_plus.round(2)} -> #{current_plus.round(2)}"
  puts "-DI: #{prev_minus.round(2)} -> #{current_minus.round(2)}"
  puts "SIGNAL: Enter long position"
elsif prev_plus > prev_minus && current_plus < current_minus
  puts "BEARISH CROSSOVER DETECTED!"
  puts "-DI crossed above +DI"
  puts "+DI: #{prev_plus.round(2)} -> #{current_plus.round(2)}"
  puts "-DI: #{prev_minus.round(2)} -> #{current_minus.round(2)}"
  puts "SIGNAL: Exit long or enter short position"
else
  puts "No crossover - trend continues"
  if current_plus > current_minus
    puts "Uptrend persists"
  else
    puts "Downtrend persists"
  end
end

Example: +DI with ADX Confirmation

high, low, close = load_historical_ohlc('MSFT')

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)
minus_di = SQA::TAI.minus_di(high, low, close, period: 14)
adx = SQA::TAI.adx(high, low, close, period: 14)

current_plus = plus_di.last
current_minus = minus_di.last
current_adx = adx.last

puts "Plus DI: #{current_plus.round(2)}"
puts "Minus DI: #{current_minus.round(2)}"
puts "ADX: #{current_adx.round(2)}"

# Strong uptrend: +DI > -DI with strong ADX
if current_plus > current_minus && current_adx > 25
  di_spread = current_plus - current_minus
  puts "\nSTRONG CONFIRMED UPTREND"
  puts "DI Spread: #{di_spread.round(2)}"
  puts "Trend Strength: #{current_adx.round(2)}"
  puts "HIGH CONFIDENCE long opportunity"

# Weak uptrend: +DI > -DI but weak ADX
elsif current_plus > current_minus && current_adx < 25
  puts "\nWEAK UPTREND"
  puts "Bullish direction but low trend strength"
  puts "CAUTION: May be choppy or range-bound"

# Strong downtrend: -DI > +DI with strong ADX
elsif current_minus > current_plus && current_adx > 25
  puts "\nSTRONG CONFIRMED DOWNTREND"
  puts "Avoid longs, consider shorts"

else
  puts "\nWEAK/NO TREND"
  puts "Wait for clearer direction"
end

Example: Uptrend Strength Analysis

high, low, close = load_historical_ohlc('NVDA')

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)
minus_di = SQA::TAI.minus_di(high, low, close, period: 14)

current_plus = plus_di.last
prev_plus = plus_di[-5]

# Analyze +DI strength changes
di_change = current_plus - prev_plus

puts "Current +DI: #{current_plus.round(2)}"
puts "5 bars ago: #{prev_plus.round(2)}"
puts "Change: #{di_change.round(2)}"

case current_plus
when 0...15
  puts "\nUPWARD PRESSURE: Very Weak"
  puts "Minimal bullish momentum"
when 15...25
  puts "\nUPWARD PRESSURE: Weak to Moderate"
  puts "Some bullish activity present"
when 25...40
  puts "\nUPWARD PRESSURE: Strong"
  puts "Solid bullish momentum building"
  if di_change > 5
    puts "ACCELERATING - momentum increasing"
  end
when 40...60
  puts "\nUPWARD PRESSURE: Very Strong"
  puts "Powerful bullish trend in effect"
  if di_change > 0
    puts "Still strengthening"
  else
    puts "May be near peak strength"
  end
else
  puts "\nUPWARD PRESSURE: Extremely Strong"
  puts "Exceptional bullish momentum"
  puts "WARNING: Watch for exhaustion at extreme levels"
end

# Check if +DI is rising or falling
if di_change > 3
  puts "\nRapidly increasing upward pressure"
elsif di_change > 0
  puts "\nGradually increasing upward pressure"
elsif di_change > -3
  puts "\nGradually weakening upward pressure"
else
  puts "\nRapidly weakening upward pressure"
end

Example: Multi-Timeframe +DI Analysis

high, low, close = load_historical_ohlc('TSLA')

# Calculate different periods
plus_di_7 = SQA::TAI.plus_di(high, low, close, period: 7)
plus_di_14 = SQA::TAI.plus_di(high, low, close, period: 14)
plus_di_28 = SQA::TAI.plus_di(high, low, close, period: 28)

minus_di_7 = SQA::TAI.minus_di(high, low, close, period: 7)
minus_di_14 = SQA::TAI.minus_di(high, low, close, period: 14)
minus_di_28 = SQA::TAI.minus_di(high, low, close, period: 28)

puts "SHORT-TERM (7): +DI=#{plus_di_7.last.round(2)}, -DI=#{minus_di_7.last.round(2)}"
puts "STANDARD (14): +DI=#{plus_di_14.last.round(2)}, -DI=#{minus_di_14.last.round(2)}"
puts "LONG-TERM (28): +DI=#{plus_di_28.last.round(2)}, -DI=#{minus_di_28.last.round(2)}"

# All timeframes bullish = strong signal
if plus_di_7.last > minus_di_7.last &&
   plus_di_14.last > minus_di_14.last &&
   plus_di_28.last > minus_di_28.last
  puts "\nALL TIMEFRAMES BULLISH"
  puts "High confidence uptrend across all periods"
  puts "Strong buy signal"

# Mixed signals
elsif plus_di_7.last > minus_di_7.last &&
      plus_di_14.last < minus_di_14.last
  puts "\nSHORT-TERM BULLISH, LONGER-TERM BEARISH"
  puts "Possible counter-trend rally"
  puts "Use caution - may be temporary bounce"

elsif plus_di_28.last > minus_di_28.last &&
      plus_di_7.last < minus_di_7.last
  puts "\nLONG-TERM BULLISH, SHORT-TERM BEARISH"
  puts "Healthy pullback in uptrend"
  puts "Potential buying opportunity"
end

Example: DI Extremes and Reversals

high, low, close = load_historical_ohlc('QQQ')

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)
minus_di = SQA::TAI.minus_di(high, low, close, period: 14)

current_plus = plus_di.last
current_minus = minus_di.last
prev_plus = plus_di[-2]

# Extreme +DI values may signal exhaustion
if current_plus > 50
  puts "EXTREME +DI READING: #{current_plus.round(2)}"
  puts "Very strong uptrend but watch for exhaustion"

  if current_plus < prev_plus
    puts "WARNING: +DI falling from extreme high"
    puts "Possible trend exhaustion or reversal coming"
  end
end

# Very low +DI in downtrend
if current_plus < 10 && current_minus > 30
  puts "MINIMAL UPWARD PRESSURE"
  puts "+DI: #{current_plus.round(2)}, -DI: #{current_minus.round(2)}"
  puts "Strong downtrend with no bullish momentum"
  puts "Wait for +DI to start rising before considering longs"
end

# Recovery from low +DI
if prev_plus < 15 && current_plus > 20
  puts "BULLISH MOMENTUM AWAKENING"
  puts "+DI recovering from low levels"
  puts "Potential trend change developing"
end

Example: Complete Directional Movement System

high, low, close = load_historical_ohlc('SPY')

plus_di = SQA::TAI.plus_di(high, low, close, period: 14)
minus_di = SQA::TAI.minus_di(high, low, close, period: 14)
adx = SQA::TAI.adx(high, low, close, period: 14)

current_plus = plus_di.last
current_minus = minus_di.last
current_adx = adx.last

prev_plus = plus_di[-2]
prev_minus = minus_di[-2]
prev_adx = adx[-2]

puts "=== DIRECTIONAL MOVEMENT SYSTEM ANALYSIS ==="
puts "Plus DI: #{current_plus.round(2)}"
puts "Minus DI: #{current_minus.round(2)}"
puts "ADX: #{current_adx.round(2)}"
puts

# Determine trend quality and direction
if current_adx > 25
  if current_plus > current_minus
    spread = current_plus - current_minus
    puts "STATUS: Strong Uptrend"
    puts "Bullish DI spread: #{spread.round(2)}"

    # Check if trend is strengthening
    if current_adx > prev_adx
      puts "TREND: Strengthening (ADX rising)"
    else
      puts "TREND: Weakening (ADX falling)"
      puts "Consider taking profits"
    end

    # Entry/exit signals
    if prev_plus < prev_minus && current_plus > current_minus
      puts "SIGNAL: New buy signal (DI crossover)"
    elsif spread > 25
      puts "SIGNAL: Very strong - hold positions"
    end

  else
    spread = current_minus - current_plus
    puts "STATUS: Strong Downtrend"
    puts "Bearish DI spread: #{spread.round(2)}"
    puts "Avoid long positions"
  end

elsif current_adx < 20
  puts "STATUS: No Clear Trend (ADX < 20)"
  puts "Market is range-bound or choppy"

  if current_plus > current_minus
    puts "DIRECTION: Slightly bullish but weak"
  else
    puts "DIRECTION: Slightly bearish but weak"
  end

  puts "STRATEGY: Wait for trend development (ADX > 25)"

else
  puts "STATUS: Developing Trend (ADX 20-25)"
  puts "Watch for trend confirmation"

  if current_plus > current_minus && current_adx > prev_adx
    puts "SIGNAL: Potential uptrend developing"
    puts "Consider early entry if +DI continues rising"
  end
end

Common Settings

Period	Use Case
7	Short-term, sensitive to recent moves
14	Standard (Wilder's original)
21	Longer-term, smoother signals
28	Very long-term trend analysis

Trading Strategies

1. Basic DI Crossover

• Buy: When +DI crosses above -DI
• Sell: When -DI crosses above +DI
• Best with: ADX > 25 for confirmation

2. Strong Trend Filter

• Only trade in direction of higher DI
• Require minimum spread (e.g., 10 points)
• Use ADX to confirm strength

3. Extreme +DI Reversals

• Watch for +DI > 50 then declining
• May signal uptrend exhaustion
• Wait for -DI to cross over before shorting

4. Trend Continuation

• +DI > -DI and both rising = strong uptrend
• Add to positions on pullbacks
• Exit when -DI crosses above +DI

5. Multi-Timeframe Confirmation

• Align +DI on multiple periods
• All periods bullish = high confidence
• Mixed signals = wait for clarity

Advanced Techniques

1. DI Spread Analysis

Monitor the difference between +DI and -DI: - Spread > 20: Very strong trend - Spread 10-20: Moderate trend - Spread < 10: Weak trend or transition

2. +DI Momentum

Track rate of change in +DI: - Rapidly rising +DI = accelerating uptrend - Flat +DI = consolidating uptrend - Falling +DI = weakening uptrend

3. DI Divergence

• Price makes higher high, +DI makes lower high = bearish divergence
• Price makes lower low, +DI makes higher low = bullish divergence

4. ADX/DI Matrix

ADX	+DI vs -DI	Action
> 25	+DI > -DI	Strong buy
> 25	-DI > +DI	Strong sell
< 20	+DI > -DI	Weak buy, wait
< 20	-DI > +DI	Weak sell, wait

Key Insights

1. +DI measures buying pressure, not price level
2. Compare to -DI, not to fixed thresholds
3. Use with ADX for complete picture
4. Crossovers work best in trending markets
5. Extreme values may signal exhaustion
6. Rising +DI shows strengthening bulls
7. Falling +DI shows weakening bulls

Common Pitfalls

1. Trading crossovers in choppy markets - Always check ADX first
2. Ignoring the spread - Small spreads mean weak signals
3. Using +DI alone - Must compare to -DI for context
4. Chasing extreme +DI - High values may mean exhaustion
5. Fixed thresholds - +DI is relative to -DI, not absolute

Related Indicators

• ADX - Average Directional Index (trend strength)
• MINUS_DI - Minus Directional Indicator (downward movement)
• ADXR - ADX Rating (smoothed ADX)
• DX - Directional Movement Index

• Complete Directional Movement Indicator (DMI)

See Also

• Back to Indicators
• Momentum Indicators Overview
• Basic Usage

• Trend Following Strategies