It is a particularly difficult aspect because the precision of stochastic parameters is much less than in other fields. There is probably also less general knowledge of the facts used in statistical interpretation than in straight numerical interpretation. But I know no research in this field. There is plenty of research which suggests that for adults coming back to it all the attitudes to straight numbers and statistics are pretty similar. To me, 'numeracy' is the broader term.
Statistical literacy is a part of numeracy.
But if the ISI is to co-ordinate then World Statistical Literacy Programme is a more appropriate name. I certainly prefer the title 'World Statistical Literacy Programme' because that is specific and clear. Also, ISI is concerned with Statistical Literacy. However, I realise that for many, numeracy includes both mathematical and statistical literacy. For example, John Allan Paulos in his book Innumeracy- mathematical illiteracy and its consequences defines innumeracy as an 'inability to deal comfortably with the fundamental notions of number and chance'.