Some Common Causes Of Confused Expression
From Handling Of Words part of The Complete Plain Words by Sir Gowers(1954)

Confusion between more and less
It is curiously easy to say the opposite of what one means when making comparisons of quantity, time or distance, especially if they are negative. A common type of this confusion is to be found in such statements as "Meetings will be held at not less than monthly intervals", when what is meant is that the meetings will be not less frequent than once a month, that is to say, at not more than monthly intervals. A similar confusion led during the war to the issue of a Control of Maps Order prohibiting the sale of maps drawn to a scale greater than one mile to the inch, instead of greater than one inch to the mile, as was intended.

Maximum and minimum sometimes cause a similar confusion, leading to the use of one for the other. An example is the following sentence, which is taken from a passage deprecating the wounding of wild animals by taking too long shots at them:

It would be impossible to attempt to regulate shooting by laying down minimum ranges and other details of that sort.

It would indeed.

Another correspondent sends, as an instance of ambiguity of a similar kind,

On the mainland of Ross the population has been more than halved in the past twenty years.

Though not actually ambiguous, this is certainly not the clearest way of saying that the population has fallen to less than half.

Expression of multiples
We learn at an early age that if we want to declare one figure to be a multiple of another the proper way of doing so is to say that the first is so many times the second, "Nine is three times three." But in later life some of us seem to forget this and to say "Nine is three times greater (or three times more) than three". Not only is this an unnecessary distortion of a simple idiom, but a stickler for accuracy might say even that it was misleading: the figure that is three times greater (or more) than three is not nine but twelve. I was moved to these reflections by the following passage:

The figure set for the production of iron ore in 1955 is 3,500,000 tons, more than twelve times greater than in 1936; for pig-iron it is 2,000,000 tons, ten times greater than in 1936; for cement 4,000,000 tons, twice as much as in 1936.

The writer of this seems to have forgotten the formula of his multiplication tables until reminded of it by finding himself up against the awkwardness of having to say "twice greater". Confusion is even more likely to be caused if percentages are used. "Production was 250 per cent greater than in 1928" leaves the reader guessing whether it was 2½ times or 3½ times as great.

By this I mean a particular form of what the grammarians call tautology, pleonasm or redundancy. Possible varieties are infinite, but the commonest example is writing "the reason for this is because.." instead of either "this is because" or "the reason for this is" than as in the first of these examples.

The Ministry of Food say that the reason for the higher price of the biscuits is because the cost of chocolate has increased.
The subject of the talk tonight will be about. . . .(A confusion between "the subject will be.. . " and "the talk will be about.. ")
The reason for the long delay appears to be due to the fact that the medical certificates went astray. (A confusion between "the reason is that the certificates went astray" and "the delay is due to the fact that the certificates went astray".)
The cause of the delay is due to the shortage of materials. (A confusion between "the cause of the delay is the shortage" and "the delay is due to the shortage".)
By far the greater majority. . . .(A confusion between "the great majority" and "by far the greater part".)
He did not say that all actions for libel or slander were never properly brought. (A confusion between "that all actions . . . were improperly brought" and "that actions . . . were never properly brought".)
An attempt will be made this morning to try to avert the threatened strike. (Those who were going to do this might have attempted to do it or tried to do it. But merely to attempt to try seems rather half-hearted.)
Save only in exceptional circumstances will any further development be contemplated. (A confusion between "only in exceptional circumstances will any further development be contemplated" and "save in exceptional circumstances no further development will be contemplated".)

The common fault of duplicating either the future or the past is a form of this error.

The most probable thing will be that they will be sold in a Government auction.

This should be "The most probable thing is that they will be".

The Minister said he would have liked the Government of Eire to have offered us butter instead of cream.

This should be "he would have liked the Government of Eire to offer....".

Qualification of Absolutes
Certain adjectives and adverbs cannot properly be qualified by such words as more, less, very, rather, because they do not admit of degrees. Unique is the outstanding example. When we say a thing is unique we mean that there is nothing else of its kind in existence; rather unique is meaningless. But we can of course say almost unique.

It is easy to slip into pedantry here, and to condemn the qualification of words which are perhaps strictly absolutes but are no longer so treated — true, for instance, and empty and full. We ought not to shrink from saying "very true", or "the hall was even emptier today than yesterday" or "this cupboard is fuller than that". But this latitude must not be abused. It is strained when an official circular defines "draining a bulk tank" as "removing the liquid contents that remain after emptying"; it is certainly carried too far in this quotation:

It may safely be said that the design of sanitary fittings has now reached a high degree of perfection.

Nor should we condone the expression more or less wholly, even though I found it in a book on style by an eminent contemporary man of letters. Nor does the comparative seem happily chosen in more virgin, which a correspondent tells me he has seen in an advertisement.

Pronouns were invented to avoid the necessity of repeating nouns. The section on Pronouns deals with this subject, and also with the device known as "the polite alias" or "elegant variation".

Unnecessary repetition of a word is irritating to a reader. If it can be avoided in a natural way it should be. For instance, in the sentence

"The Minister has considered this application, and considers that there should be a market in Canada",

the repetition of "consider" gives the sentence a clumsy and careless air. The second one might just as well have been "thinks". It would have been easy also to avoid the ugly repetition of essential in the sentence

"it is essential that the Minister should have before him outline programmes of essential works".

But where the same thing or act is repeatedly mentioned, it is better to repeat a word than to avoid it in a laboured and obvious way.

Irritating repetition of a sound (assonance) is usually mere carelessness.

The controversy as to which agency should perform the actual contractual work of erection of houses.
Reverting to the subject of the letter the latter wrote..... . (This is indefensible because it could so easily be avoided by calling "the latter" by name.)
Since a certain amount of uncertainty still appears to exist.

This is not even true, for I feel sure that what really existed was an uncertain amount of uncertainty.