"Agile by the numbers - what people are doing" was a talk by the enjoyable spikey Scott Ambler. Scott had been running some surveys to try and get to the bottom of what agile teams were actually doing - as opposed to what they claimed to be doing. Scott hypothesised that there's a bit of a macho developer culture which perhaps inhibits the ready dissemination of truth :)

His findings:

• 76% of organisations "do agile" - it's not a marginal practice any more;
• Within these organisations, only 44% of the teams are "doing agile" (he doesn't try and define what this actually means, this is according to the teams definition of agile);
• Teams of up to 10 developers tend to succeed more: agile seems to be easier with smaller teams. But that said, there are lots of people succeeding with larger teams;
• Most agile processes *are* empirical;
• 3/4 of teams using agile are doing legacy projects - i.e. it's not only used for greenfield development;
• Only 42% of agile teams are colocated - another 42% are driving distance or further apart;
• 56% of agile teams produce documentation in the form of a "vision document";
• The average agile project takes 3.9 weeks to warm up, before code starts being written - developers aren't typically diving into building stuff immediately;
• According to a fairly exhaustive DDJ survey, agile works better than other methods;
• 70% of projects are accurate to within 30% of their best estimate. The other 30% of projects are less accurate. But most businesses require projects to be accurate to within 9% of the original estimate;