Fair Value Gap vs Supply and Demand
Fair value gaps are defined by a three-bar rule where the outer bars do not overlap. Supply and demand zones are drawn around the area a move originated from, using judgement, so one is checkable and narrow while the other is wider and interpretive.
Both mark a part of the chart a move came from. One is defined by a rule you can apply mechanically; the other is drawn by eye, which is more flexible and much harder to hold yourself to.
What each one is
A fair value gap is a three-bar pattern. The middle bar moves far enough that the first and third bars do not overlap, leaving an untraded band with exact boundaries. Fair value gap covers the rule.
A supply or demand zone is the area a move originated from, usually a consolidation, drawn around it with judgement about where it starts and ends. Supply and demand covers it.
Both are answering the same question. Where did this move begin, and might price react there again — one with a formula, one with an eye.
Where they differ
Whether the boundaries are exact. The gap’s edges are two specific prices. A zone’s edges are chosen, and two people draw different ones on the same chart.
How wide the area is. The gap is usually narrower — on this site’s shared series the median bar range is 0.493, and a gap is a fraction of the move that created it.
What that width does to the stop. A narrow band gives a tight invalidation and a larger position for the same risk. A wide zone gives room and a smaller position.
Whether it can be tested. A rule can be run over history and counted. A zone drawn by judgement can only be illustrated, which is why the examples always come from the past.
Where they agree
Both mark where a move started. Plot both and the gap frequently sits inside the zone, because they are describing the same event at two resolutions.
Both are locations, not signals. Price arriving is the beginning of a decision, and neither concept tells you what to do next.
Both are frequently ignored. Direction runs average 2.01 bars here with a longest of 11, and price travels through marked areas constantly.
And neither supplies a stop. The ninetieth percentile bar range here is 1.101 and the largest single bar was 2.338, which is what any nearby invalidation has to survive.
Which one to use
Use the zone when you want room to be roughly right. An area that survives ordinary movement keeps you in trades a tight band would have ended, at the cost of a smaller position.
Use the gap when you intend to keep a record. A stated rule is the difference between a method and an impression, and it is the only version of this idea you can review honestly.
Use a gap sitting inside a zone. When both mark the same area you have a checkable entry and a wider context, which is the strongest version of either.
And when the zone is drawn because you wanted a trade there, do not take it. A zone with no rule behind it can be placed wherever it needs to be, which is the failure this whole comparison turns on.
Why a checkable rule is worth the narrowness
Because an undefined area is always available. Look for a zone on any chart and you will find one, which means it can never be wrong and therefore never tells you anything.
And because a rule can fail. The three-bar version can be counted, run over history, and shown not to work on your instrument — which is what makes it worth something when it does.
What each rule has to say
For the gap: whether wicks count, and on which timeframe. Those two answers change the count enormously, and they are the whole specification.
For the zone: where it starts and ends. The base of a consolidation, the last candle body, the whole range — pick one and write it down before the next chart.
For both: how large the move has to be. A band left by a small move is not the same event as one left by a decisive one, and the ninetieth percentile bar range here is 1.101.
And for both: an expiry. Without one, every area ever marked stays on the chart, and a chart with a hundred areas has none.
The original data
Of the 24,971 unique videos in research/search-study-corpus.jsonl, no title compares these two
directly — this pair is constructed from two subjects the corpus covers separately. Separately, fair
value gaps appear in 150 titles at a median of 28,170 across 108 channels, and supply and demand in 130
at a median of 13,963 across 93. The counts come from site/corpus_count.py.
150 videos on one at 28,170 and 130 on the other at 13,963. Similar coverage and double the audience per video for the version with a stated rule — a rare case in this corpus where the checkable idea also draws the larger audience.
The answer to the question on that chart is whichever one you will still honour. A tight stop you widen under pressure is worse than a wide stop you sized for — because the position came from a number you did not keep.
When it fails
The failure is sizing from the narrow band and defending with the wide zone, and it multiplies the loss. The position is calculated from the gap’s boundaries, which allows a large size. Price goes through, and because the zone is also on the chart the trade is held on the grounds that the real invalidation is further out. The size was set for the small stop and the loss arrives at the large one, several times what the plan specified.
The second failure is drawing zones after the move. Everything works backwards.
A third is loosening the three-bar rule. Every fast move then qualifies.
A fourth is no expiry. Areas accumulate until the chart is unreadable.
A fifth is trading a band smaller than the round trip. The cost exceeds the target.
And a sixth is expecting a return. Many marked areas are never revisited.
Related
Fair value gap covers the three-bar rule. Supply and demand covers the drawn zone. And imbalance covers the broader idea both belong to.
The thing that separates these for me is reviewability. Ten trades from a stated three-bar rule are a sample. Ten trades from zones you drew by eye are ten anecdotes, because next month you will not be able to say what made those particular zones qualify.
— Michael Whitman
This page is educational, not financial advice. Test every idea on your own charts before risking money.