There's a way of meaasuring the complexity of writing called the 'fog factor'. It's based on some calculation based on sentence length in a sample, as well as the number of polysyllabic words. But I seem to think there are other rules, like 'higher' is derived from 'high' so doesn't count as 2 syllables. Or something like that anyway.

As far as I remember, the factor is an indication of the number of years formal schooling the reader would need to be able to cope with the work; so 12 would mean high-school, 15-16 a B degree etc.

I wondered if anyone had come across an automatic tool for doing the calc: type or scan some text in, and Voila! the Fog Factor is x ??