I do not have much idea on what the larger organizations do, but here's what I've done in the past (and it works fairly well)
Speak to your recruitment agencies. Since they work with various companies, they have a fairly good idea of the current compensation trends.
Keep your records: when you contact candidates, you must be asking for their current remuneration details, if you can keep a sheet where the data is captured, you can recognize the trend.
Utilize job sites for more than talent sourcing: Most job sites have a lot of data about a candidate. you can utilize this data too to understand the trends.
This will also help you understand which organizations are on the higher end and which are on the lower end and what are the average salaries.
Revisit your own model: check on the salaries that you were paying about a year ago or 6 months ago for a particular level of experience, with specific skill set or a certain work field. This data will help you understand the general rise in salary levels over a period of time.
Hope this is of some help.