Highs, Lows and Trend Structure

The short answer

An uptrend is a sequence of higher highs and higher lows. A downtrend is a sequence of lower highs and lower lows. When neither sequence holds, the market is in a range.

That is the entire vocabulary. It is worth having because it replaces "the market looks strong" with something two people can check independently and disagree about productively.

Defining a swing point

Before you can identify higher highs you need a rule for what counts as a high. "It looks like one" is not a rule; it produces different structures for different observers and, more damagingly, different structures for the same observer on different days.

A common mechanical definition: a swing high is a candle whose high exceeds the highs of the N candles either side of it. N is a parameter you choose — 2, 3 and 5 are all common. Larger N gives fewer, more significant swings.

Two consequences follow immediately:

1. Structure depends on your parameter. A chart analysed with N=2 has more swing points and more structural breaks than the same chart with N=5. Neither is correct; they are different resolutions. Pick one and keep it.
2. Confirmation is always late. A candle only becomes a swing high once N further candles have printed without exceeding it. You never identify a swing point in real time.

That second point is not a defect to engineer around. It is what it costs to have an objective definition rather than an impression.

Break of structure

In an uptrend, price making a lower low breaks the sequence. The description "higher highs and higher lows" no longer applies.

What this establishes: the previous description has failed.

What it does not establish: that a downtrend has begun. A downtrend needs its own sequence — lower highs and lower lows — and until that sequence forms, the market is simply not describable as either. A great many "trend reversal" calls are made in this gap, where the old description has broken and the new one has not formed.

Being comfortable saying "there is no clean structure here right now" is more valuable than it sounds. It is the state markets spend a great deal of time in, and it is the state in which most unnecessary trades get taken.

The retro-fitting problem, again

Because swing points are confirmed late and their definition is a parameter, structure is unusually easy to redraw after the fact. A trader long in a position that is falling can nearly always find a swing-point definition on which the uptrend is still intact.

The guard is procedural, not analytical: write your swing definition and timeframe into your plan, and mark your structure before entry. If the structure later changes under a definition you fixed in advance, that is information. If it changes because you changed the definition, that is rationalisation with extra steps.

What structure is for

Not prediction. Structure gives you two practical things:

• A shared, checkable description of what price has done, which makes journal entries and post-trade reviews meaningful.
• A natural invalidation level. If your reason for being long is "the uptrend structure is intact", then the most recent higher low is exactly where that reason fails. That is a stop with a meaning attached, which is what the invalidation lesson argues for.

The market-structure vocabulary has accumulated a lot of branding. Underneath it, this is the substance: a precise way of saying what happened, and a defensible place to be wrong.