A measurable comparison needs a baseline
A reproducible numerical comparison needs values X and Y and a way to express difference N. X is the compared quantity, Y the baseline, and N a percentage, point difference or multiplier. These can be explicit in the sentence or unambiguously available from a table or context.
English introduces the baseline with than (higher than in 2019), compared with, relative to, versus or against. All require an identifiable group, period or level. On the previous occasion or before does not identify a baseline unless the reader knows which occasion is meant.
Check that the reader knows what is compared and which difference is intended. Supply relevant data when an exact calculation is needed. Far, much and considerably are valid without compulsory replacement by a number.
X was N% higher than Y.
Grant income was 11% higher than in the previous funding cycle.
Grant income was 11% higher than in the previous funding cycle.
The number, baseline (previous funding cycle) and direction are stated together.
Relative to the pre-reform period, appeal rates fell by a third.
Relative to the pre-reform period, appeal rates fell by a third.
Relative to establishes the baseline before the number.
Compared with the dry season, river flow in the wet season was 2.4 times as high.
Compared with the dry season, river flow in the wet season was 2.4 times as high.
The sentence opens with the baseline; as … as expresses the multiplier.
Three measures of difference: percentages, points and ratios
Three ways to express a difference are not interchangeable. A relative difference (N% higher) divides the difference by the baseline. An absolute difference between percentages (N percentage points) subtracts them. A ratio (N times as high as, a factor of N) divides one value by the other.
An increase from 40% to 50% is 10 percentage points or 25% of the starting 40%. In precise quantitative writing, “up 10%” would instead mean a change from 40% to 44%. Use percentage points when subtracting percentage values.
Direction and baseline change the number: if B is 25% greater than A, A is 20% smaller than B, rather than 25%. What follows than determines the denominator, rather than merely decorating the sentence.
N% higher than Y · N percentage points higher than Y · N times as high as Y · exceeded Y by a factor of N.
Participation was 8 percentage points higher among women than among men.
Participation was 8 percentage points higher among women than among men.
An absolute difference between two proportions.
Material costs were 30% higher than the budget allowed.
Material costs were 30% higher than the budget allowed.
A relative difference calculated from the budget baseline.
Peak load exceeded the design limit by a factor of 1.5.
Peak load exceeded the design limit by a factor of 1.5.
A ratio expressed with exceeded … by a factor of.
Output at the new plant was 20% lower than at the old one, so the old plant produced a quarter more.
Output at the new plant was 20% lower than at the old one, so the old plant produced a quarter more.
Changing the baseline changes the percentage: 20% and 25% describe the same pair of values.
The times more trap: express ratios unambiguously
Some readers interpret three times more than and three times higher than as ×3; others read them as ×4, the baseline plus three baselines. Three times greater than occurs with both interpretations in published writing. Precise prose chooses wording that leaves no such choice.
Three clear options are available. Use an as … as pattern: three times as high as, three times as many as, three times as much as. Plural countable nouns take many; uncountable nouns take much. Alternatively, use exceeded Y by a factor of three or a multiplier adjective such as threefold in a threefold increase.
For fractions, use half as many as, a third as long as or one-fifth as costly as. Half as … as clearly expresses half the quantity. Formal comparisons of separate countable items normally use fewer participants, while less is natural for aggregate measurements: less than ten minutes.
N times as high as Y · N times as many as Y · exceeded Y by a factor of N · N-fold.
The second trial enrolled four times as many volunteers as the first.
The second trial enrolled four times as many volunteers as the first.
A countable noun takes as many … as.
Imports exceeded exports by a factor of six.
Imports exceeded exports by a factor of six.
The multiplier is stated once and linked to its baseline.
Commuters here spend half as much time in traffic as in the capital.
Commuters here spend half as much time in traffic as in the capital.
A fraction with as … as and uncountable time.
Energy demand rose twelvefold between 1960 and 2020.
Energy demand rose twelvefold between 1960 and 2020.
Twelvefold is an adverb here, expressing a twelvefold rise in demand.
Form: comparatives, as … as and modifiers
A standard academic comparative uses -er (higher) or more (more reliable), rather than both. Double forms such as more higher and most highest are not standard in this register. A superlative likewise uses most or -est, rather than both.
In as … as, use the adjective’s base form: as high as, not as higher as. Comparative higher can take a than-phrase or a baseline understood from context: prices are higher now. Negatives include not as … as and not nearly as … as.
Far, much, considerably, markedly, slightly and a good deal can modify a comparative. Very higher is not the standard pattern; very much higher is correct. A modifier can remain qualitative if no exact number is required. Formal counts of separate items normally use fewer, while uncountable quantities use less.
Far / slightly + comparative (+ than and baseline) · as + base adjective + as.
- adjective —
- A word describing what someone or something is like: happy, tired, interesting.
The northern grid was considerably more reliable than the southern one.
The northern grid was considerably more reliable than the southern one.
A modifier precedes a comparative formed with more.
This model is not nearly as efficient as its predecessor.
This model is not nearly as efficient as its predecessor.
A negative as … as comparison with a base-form adjective.
The audit found slightly fewer errors than in the previous year.
The audit found slightly fewer errors than in the previous year.
Fewer accompanies countable errors.
Capacity at the new terminal is double that of the old one.
Capacity at the new terminal is double that of the old one.
Double followed by that of keeps the compared quantities equivalent.
Compare like with like
The baseline after than must be comparable with the initial quantity. The output of this mill was higher than the old mill compares output with a mill, which is not a meaningful numerical comparison.
Three patterns preserve equivalence: repeat the noun (than the output of the old mill), replace it with singular that or plural those (than that of the old mill), or reduce to a prepositional phrase (than at the old mill). A possessive such as than the old mill’s also works.
Parallel construction clarifies the quantities, but the two parts need not use identical grammatical forms. Costs were higher than we expected compares actual with expected costs through a clause.
X of A was higher than that of B · X in A was higher than in B.
Salaries in the public sector grew faster than those in the private sector.
Salaries in the public sector grew faster than those in the private sector.
Those refers to salaries.
The rainfall of the 1990s was heavier than that of the 1980s.
The rainfall of the 1990s was heavier than that of the 1980s.
That refers to rainfall; the two periods are presented in parallel form.
Turnover per employee was 30% higher at the firm than at its main competitor.
Turnover per employee was 30% higher at the firm than at its main competitor.
Parallel prepositional phrases: at the firm and at its main competitor.
Superlatives: highest within a group
A superlative identifies an extreme within a group explicitly named or understood from context: of the seven reactors, among the countries surveyed, in the sample. Formal comparisons of two traditionally favour the higher of the two, but the highest of the two also occurs, so “at least three” is not a universal grammatical ban.
Before a noun, a superlative often takes the: the highest rate. A possessive replaces the article: our highest rate. Predicative inflation was lowest in March and adverbial the eastern line ran fastest are possible. Use by far the cheapest for emphasis, the second-highest for rank, and one of the fastest-growing sectors for membership among leaders, with a plural noun.
The highest result among five regions could also be the world’s highest, but the first claim does not prove that. Establish the comparison’s limits, especially when the conclusion concerns a sample.
The + superlative + comparison group, explicit or understood from context.
Of the seven reactors inspected, Unit 3 had the oldest control system.
Of the seven reactors inspected, Unit 3 had the oldest control system.
Of introduces the group at the beginning.
The Baltic route was by far the cheapest of the three options.
The Baltic route was by far the cheapest of the three options.
By far intensifies the superlative; the group is three options.
Country D was the second-largest importer among the nations surveyed.
Country D was the second-largest importer among the nations surveyed.
A ranked superlative with a group introduced by among.
It was one of the three fastest-growing sectors in the sample.
It was one of the three fastest-growing sectors in the sample.
One of the limits the claim and identifies its scope.
Boundaries with related topics
This lesson builds the comparison itself: a difference, its size and baseline. Approximation (about, roughly) and numerical precision belong to a separate lesson on exact and approximate quantities. Limits such as at least, no more than and up to are covered by qualified quantification.
Approximation and limits can combine with comparison. Roughly 15% higher still needs a clear baseline, but need not repeat it in the same sentence if a previous passage or table establishes it unambiguously.
Compared quantity + clear baseline + size of difference when needed.
Wages were roughly 15% higher than in 2019.
Wages were roughly 15% higher than in 2019.
Approximation modifies the number; the baseline comparison structure stays unchanged.
The gap in funding was at least twice the 2019 level.
The gap in funding was at least twice the 2019 level.
A lower bound modifies the ratio; the baseline is the 2019 level.
Common mistakes
Incorrect:Wages in the capital were twice as higher as in the provinces.
Correct:Wages in the capital were twice as high as in the provinces.
Between as … as, use base form high. Higher can occur with than or without an explicit than-phrase when the baseline is understood.
Incorrect:Rents in Oslo were higher than Bergen.
Correct:Rents in Oslo were higher than those in Bergen.
Than is followed by a city, but the comparison needs rents. Use those in or than in Bergen to compare corresponding quantities.
Incorrect:Unemployment fell by 2% last year, from 9% to 7%.
Correct:Unemployment fell by 2 percentage points last year, from 9% to 7%.
The difference between two percentages is measured in percentage points. A 2% decrease from 9% would be only 0.18 percentage points.
Incorrect:Site 4 had the most high emissions among the nine sites.
Correct:Site 4 had the highest emissions among the nine sites.
The standard superlative of high is highest. This is that adjective’s pattern, rather than a universal rule for every short adjective.
Incorrect:Group B had less participants than Group A.
Correct:Group B had fewer participants than Group A.
Participants is countable; the formal comparative of its quantity uses fewer rather than less.