What tips do you have to quickly learn about the culture of a client organization? Currently, I use my intuition, supplemented by several validated culture assessment instruments.
This is a great question because even the most experienced consultant needs a robust understanding of the culture(s) of an organization prior to investigating processes, structure, strategy, etc. Validated assessment instruments are certainly one way of getting a sense of a place, but these require experience to appreciate the nuances of a culture, and these vary widely in their validity and usefulness. Certainly, there are a lot more things going on than a single assessment tool can tell you.
Consider using humor. By that I mean that your understanding of the type of humor various individuals and groups use within an organization provides a powerful insight into its culture. Supposedly humor is a reflection of pain, so humor must also be a reflection of the source of that pain and the way an organization chooses to deal with it.
Is the use of humor acceptable for all staff or just the leaders? Does everyone "get" the jokes? Is the humor lighthearted and positive, or disparaging and mean-spirited? Are jokes made at the expense of individuals, either within or outside the organization? What cartoons are posted in the break room or at the executive assistant's workspace? Are disparaging jokes made about consultants to your face the first day you arrive? Does humor have undertones of racial, gender, age or other targets of discrimination? Is it highbrow or vulgar? You should be able, within a few days at a site, to get a good sense of the culture by looking at a complete picture of how humor is used.
Tip: Create an informal log of how humor is used as you begin an engagement. Start with any use by client personnel leading up to your engagement. Note who creates humor, to what (or whom) it is directed, and how it differs across the organization. Draw your conclusions, perhaps after discussing your findings with a colleague who does not know the client. To the extent that humor is lighthearted, this may indicate an easygoing organization with relatively few conflicts. Then again, it may also signify a shallow communication style. After a few clients to calibrate your approach, you will improve your rapid culture assessment capabilities. Another tool in your consulting arsenal.