Elder Force Index: Why Equal Volume Gives Unequal Force

Published November 14, 2026 · AlgoWay

Two bars can trade the same volume and contribute the same increase to OBV, yet produce very different Elder Force Index values. The missing ingredient is how far the closing price moved. Force Index multiplies that change by volume; OBV uses the direction of the change.

That difference matters before TradingView alert automation. A rule based on positive Force Index is not interchangeable with a rule based on rising OBV. When preparing a signal for AlgoWay's TradingView alert workflow, define the indicator calculation and event first. The execution instruction cannot settle an argument between two different signal definitions.

Separate raw force from the smoothed line

TradingView's Elder Force Index reference defines raw force as the current close minus the previous close, multiplied by current volume. Its standard EFI uses an exponential moving average of that series, with a default length of 13.

Raw force = (current close - previous close) * current volume
Smoothed force = EMA(raw force, chosen length)

The raw calculation is positive after a higher close, negative after a lower close, and zero after an unchanged close. The smoothed line also reflects earlier bars. Do not apply the raw sign rule to a smoothed value as though its history had been erased.

Equal volume, different price distances

Consider three independent hypothetical bars. Each starts from a previous close of 100 and has volume of 1,000 units. These are arithmetic examples, not market observations or backtest results.

The larger rise creates twenty times the raw force of the smaller rise. OBV adds the same 1,000 in both cases. Neither calculation is broken: they retain different information from the same bar.

TradingView's OBV formula adds or subtracts the whole volume according to the close-to-close direction, then carries that running total forward. Force Index instead gives each bar a price-distance weight before smoothing. For the equal-close case and its consequences, see why high volume can leave OBV unchanged.

The units also matter. Raw force here has units of price multiplied by volume. If an otherwise identical price series is multiplied by ten while volume stays fixed, its raw force becomes ten times larger. A threshold of 500 therefore does not acquire a universal meaning simply because several instruments display the same indicator name.

An up bar can leave the smoothed reading negative

For a 13-period EMA, the usual recursive weight on the new observation is 2 / (13 + 1), or 1/7. Suppose the preceding smoothed force is -700 and the new raw force is +100. The next smoothed value is:

(1/7 * 100) + (6/7 * -700) = -585.714...

Price rose, raw force is positive, and the smoothed indicator is still negative. It has risen from -700, but it has not crossed zero. If the next raw force is +4,000, the following smoothed reading is about +69.39. That is a zero crossing. This example begins with an assumed existing EMA value; it does not specify how a platform initializes the first observation.

The distinction gives three separate candidate rules: raw force above zero, smoothed force rising, and smoothed force crossing above zero. On the first update in this example, the first two are true and the third is false. A chart label saying “bullish force” leaves rather a lot to the imagination of a machine.

Turn the reading into one precise event

A testable example is: evaluate at the chart bar's close; require the previous 13-period smoothed value to be at or below zero and the current value to be above zero. That describes a crossing event. Requiring only a positive current value describes a state that can persist for many bars. Neither rule is a demonstrated profitable strategy.

Record the symbol and data feed, chart timeframe, volume input, smoothing length and event timing. TradingView documents that indicators update during realtime bars; a bar-close rule must wait for confirmation rather than act on a temporary intrabar sign. Check that the selected alert condition actually expresses the intended event.

Before connecting an execution route, record the prior and current readings beside each expected signal. Then compare those events with the alert log. A positive value, a rising value and a zero crossing should never share a test label merely because all three look encouraging on a chart.