What grammatical range and accuracy means

Grammatical range and accuracy is a quarter of your writing and speaking score, and it measures two things that pull against each other.

Range means using a variety of structures: not every sentence simple, not every sentence the same shape. Accuracy means they are correct.

The trade off candidates get wrong. Attempting complex structures badly scores worse than using simpler ones correctly. A band 7 answer contains a mix of simple and complex sentences, most of them error free. An answer full of attempted complexity with errors in most sentences scores lower than a plain one.

So the strategy is narrow. Master four or five structures properly, use them accurately, and add variety from there. Not twenty structures used shakily.

The examiner is counting error free sentences, roughly. At band 6 some sentences are error free; at band 7 the majority are and errors do not impede communication; at band 8 the great majority are.

Which means the fastest route to a higher band for most candidates is not new grammar. It is eliminating repeated errors, because most people make the same five or six mistakes over and over, and fixing those changes the proportion of error free sentences immediately.

Find your own five. Write three practice answers, have them marked or check them carefully, and list every error. The list will be short and the same errors will appear in all three.