Comparative and correlative structures

Comparisons do more than rank two things. They can show that changes move together, that a difference grows or shrinks, or that a quality reaches the same degree. Small changes in the frame can change the logic, so identify the relationship before choosing the words.

A magnifying glass finds more clues while a verdict stamp grows less certain beneath ‘The more clues emerge, the less certain the verdict becomes.’ — The more clues emerge, the less certain the verdict becomes: the two changes move together.

Show two changes moving together

The correlative pattern has two linked parts:

The more carefully the evidence is examined, the less certain the original conclusion appears.
The longer the negotiations continued, the harder agreement became.

Each half has the + a comparative form. The first describes a changing condition; the second describes the corresponding result. A comma commonly separates the two halves when the first comes before the second.

Do not leave out the in the formal pattern:

Incorrect: More we learn, less we know.
Correct: The more we learn, the less we know.

Both halves need a clear comparison. You can compare adjectives, adverbs, nouns or whole clauses: The more detailed the evidence, the more persuasive the case.

Repeat a comparative to show a gradual change

Use comparative + and + comparative when something changes progressively:

The distinction is becoming increasingly difficult to defend.
As the deadline approached, the revisions grew more and more substantial.

For a two-part relation, use the...the. For gradual change in one quality, use more and more / less and less or an -er and -er form when natural: thinner and thinner, more and more complicated.

Compare equal or unequal degree

Use as + adjective/adverb + as for equality:

The revised model is as sensitive to small changes as the original one.

Use not as/so + adjective + as to say something falls short:

The second estimate was not as reliable as the first.

Use a comparative + than for a difference:

The revised estimate is more robust than the preliminary one.

In careful English, do not use as after a comparative:

Incorrect: This estimate is more reliable as the earlier one.
Correct: This estimate is more reliable than the earlier one.

Avoid false comparisons

The two items must belong to the same comparison. A sentence such as The population of the city is larger than the neighbouring town compares a population with a town. Write larger than that of the neighbouring town or the city is larger than the neighbouring town.

Common mistakes

The more we investigate, clearer the pattern becomes. Add the second the: the clearer.
The analysis became more clearer. Do not stack more on an -er comparative: clearer.
The more ambitious the target, costs rise. The second half needs its own comparative relation: the higher the costs.
Her conclusion is no more convincing as mine. Use than mine.

Quick check

Complete each relationship with the correct comparative frame.

The closer the two estimates are, the ______ it is to distinguish them.
As the evidence accumulated, the explanation became ______ and ______ plausible.
This interpretation is no less defensible ______ the alternative.
The response time of the new system is shorter than the old system.

Possible answers:

the harder — the two changes are linked.
more and more — the plausibility increases gradually.
than — no less ... than expresses an equal or greater degree.
that of the old system — compare response time with response time, not with the system itself.

Read the relationship before you build the comparison

The the … the … frame links two changing scales. It does not simply mean “very” and it is not a normal if-clause. The first comparative sets a condition or measurement; the second gives the corresponding change:

The more evidence we collect, the more confidently we can distinguish a pattern from a coincidence.

Imagine moving along the first scale: as the quantity of evidence rises, confidence rises too. The two changes may move in opposite directions:

The less closely the groups are matched, the harder the results are to compare.

The pattern can include a noun phrase, adjective, adverb or full clause. Keep the before both comparative parts, even when the comparison follows a noun:

The more complex the model, the greater its need for reliable data.
The sooner the team agrees on definitions, the less time it will waste later.

The opening half sets up the relationship; the second half completes it. A comma is usual when the first half comes before the second.

Do not confuse the two comparative patterns

Use the + comparative, the + comparative for linked change:

The more we discussed the problem, the clearer its cause became.

Use comparative + and + comparative for one quality that intensifies over time:

The cause became clearer and clearer as more records emerged.

The first sentence relates two measures; the second tracks one quality. Avoid mixing the frames: write the problem became clearer and clearer or the more we discussed it, the clearer it became.

Compare like with like

A comparison must have a recoverable point of comparison. If the first half names a response time, the second half should name another response time, not the whole machine:

The new system responds faster than the old system does.
The response time is shorter than that of the old system.

Use that for a singular or uncountable noun and those for a plural noun when you need a substitute: the cost of the new plan is lower than that of the old one. This avoids an illogical comparison while keeping the sentence concise.

Be alert to the scope of no more / no less. No less reliable than means at least equally reliable. No more reliable than can mean no better than, and may suggest criticism. The negative word changes the evaluation, not only the degree.

Guided practice

Complete both parts: The less clearly the instructions are written, ___ likely users are to make mistakes.
Rewrite to compare matching things: The battery life of this phone is longer than the previous model.
Choose the frame for a gradual rise in pressure: The pressure became (the higher / higher and higher).
Complete: The more carefully a claim is qualified, ___ misleading it is likely to be.

Answers and reasoning

the more. Both halves need the and a comparative.
The battery life of this phone is longer than that of the previous model. The comparison is between battery lives.
higher and higher. Only one quality is changing.
the less. The second scale moves in the opposite direction.

Comparative forms are not always made with more

Use the comparative form that belongs to the adjective or adverb: higher, clearer, less reliable, more accurately. Short forms often take -er; longer forms generally take more/less. Avoid double marking such as more clearer or less easier. If the form is irregular, keep it intact: the better the evidence, the stronger the inference.

The correlated halves can be short, with some words understood:

The sooner, the better.
The more, the merrier.
The longer the delay, the worse.

These compact expressions rely on a familiar relation. In a technical explanation, spell out the missing idea when it is not obvious: The longer the delay, the more difficult it becomes to reconstruct the sequence.

Correlation does not prove causation

The structure expresses a relationship in the speaker’s description; it does not by itself show that one change causes the other. The more people use the service, the more expensive it becomes links two trends, but a report still needs evidence to establish why they are linked. Use as or with where it helps distinguish a trend from a cause:

As demand increases, the service becomes more expensive.