loss

Measures the magnitude of negative change from the previous bar. When price falls, loss() returns the absolute amount of the decline as a positive number. When price rises or stays flat, it returns 0. This isolates downward movement for analysis, and is a core building block for RSI and other momentum indicators.

Parameters

• source (field): Data series to measure (typically close)

Formula

loss = abs(min(source - source[1], 0))

If today's price < yesterday's: loss = |difference|
If today's price >= yesterday's: loss = 0

Examples

Filter for Down Days

Find stocks that closed lower than the previous day:

// stock declined today
loss(close) > 0;

Significant Downward Movement

Find stocks with large single-day declines:

// lost more than $2 today
loss(close) > 2;

Cumulative Losses

Track total losses over a period using sum():

// total losses over last 14 days
sum(loss(close), 14) > 10;

Gain vs Loss Comparison

Compare today's downward vs upward movement:

// today was a down day (loss exceeded gain)
loss(close) > gain(close);

Returns

Float >= 0 (the absolute price decline, or 0 if price didn't fall)

Notes

• Always returns a non-negative value (losses are expressed as positive numbers)
• Returns 0 on the first bar (no previous bar to compare)
• Use with sum() or wilderma() to aggregate losses over time

See Also