Hello all,

I've been having a look at the REC index data that gets posted regularly to the news page on this site about IT contractor demand.

I've seen the basic explanation for it (50+ = more jobs than last month, <50 means less jobs than last month) , but does anyone know exactly how the index is calculated? For example, how can you combine multiple months of data, to calculate an overall rate of decrease (or increase) ?

Thanks for any pointers.