A cropped knit and a high waisted trouser work because the two hems meet and create a single continuous line at the waist. If there is a gap, the outfit becomes about the gap. If the knit overlaps the waistband by several centimetres it stops being cropped and simply looks short. The target is a knit ending at or just below the top of the waistband, which means the two garments have to be chosen together rather than separately. Where people go wrong is buying a very short knit and a mid rise trouser, which leaves a band of skin that was not the intention. The other variable is the trouser rise itself, since a genuine high rise sitting at the natural waist is what makes the proportion work and a false high rise sitting on the hip does not.

A cropped knit needs enough weight to hold a straight hem, because a fine knit will roll at the bottom edge and a rolled hem on a cropped piece looks unfinished. A ribbed hem is the most reliable. On the trouser, a wide or fluid leg balances a cropped top well, since the volume below offsets the shorter top half and the eye reads it as deliberate. A slim high waisted trouser with a cropped knit is a much tighter silhouette and needs the fit to be right at both ends. Sleeve length is worth a thought too, since a long sleeve on a cropped body reads considered while a cropped sleeve on a cropped body shortens everything. And a knit with any structure through the shoulder does more for the outfit than a soft one.

This is a proportion we like and one we have narrowed considerably, to a ribbed knit ending exactly at the waistband and a wide high rise trouser in a heavier fabric. Tried the other way around, with a fine knit and a slim trouser, it needs everything to be perfect. It is also worth checking the outfit seated and with arms raised, since a cropped knit that sits correctly standing can rise several centimetres in either. On colour, keeping both pieces in the same family makes the waist meeting point less conspicuous. If you take one thing away, buy the knit and the trouser as a pair, because the whole effect depends on where the two hems meet.