It's a little tenuous as it's very hard to scientifically measure ROI but for the four stages ..
1. reactions – ‘liking or feelings for a programme’ - the usual "happy sheet" which generally I do via survey monkey as the stats it comes out with are so easily reportable and saves time for me playing about in excel with the data. Also we've noticed a 15-20% increase in our response rate using survey monkey compared to a form via our website, not sure why as both are online but people like survey monkey! Questions are things like - did you feel there was enough of a mixture of theory and practical, did you like the venue, was the packs provided ok etc etc
learning - ‘principles, facts etc absorbed’ - still using survey money and questions are usually something like - what 3 things did you learn that were most helpful, what stood out the most for you, which session was most helpful and why
behaviour - ‘using learning on the job’ - again via survey monkey but I follow up around 3 months later saying 'remember you went on our course - have you done anything back in the workplace as a result of attending? What was it? If you didn't what stopped you?.
results - ‘increased production, reduced costs, etc’. - at the same time (3 months after event) I would ask about their opinion if the impact of things they have done, influenced by what they learnt at the workshop, has made their work quicker or more efficient - you could do this on a scale to quantify it so asking them on a scale of 1 to 5.
I also speak to others - not just those who attended the event. So somehow getting on contact with the organisations to see if they have noticed any difference. But I have links into this so it's not cold calling it's just part of the relationship management.
Hope that helps!