A lot of things we do by habit are flawed, mostly out of ignorance. Peeling a banana. Folding a fitted sheet. Making a BLT sandwich. Just look at LifeHacks: You're Doing It Wrong.
Along these lines, the latest fail is that handy rule of thumb that real estate professionals use for estimating rentable square feet (RSF) for corporate offices -- RSF/Person. It doesn't work anymore. One Person = One Seat is over.
To estimate square footage now you need to know how many days per week each person will be on-site. Occupancy profile is more important than office size for determining actual space needs.
Let’s say there are three kinds of people: Resident, Mobile, and Drop-in. The table below shows a range of occupancy scenarios – 0% mobile, 20% mobile, and 40% mobile. For simplicity, Drop-in count is set to zero. Total headcount is set at 150. The resulting seat requirement and RSF requirement for each scenario shows how a mobile workforce affects real estate.
To calculate the RSF requirement start with the days per week that each member needs a seat. For residents the number is five (days in the work week). For mobile members it's some number less than five. The model uses 2.5 (half-time on-site.) Vacancy rate also affects the seat requirement and is set at 10%. Vacant seats are essential for staffing flexibility and are available for mobile members.
This algorithm generates the new metric: RSF/Day. Note that RSF/Day is 50 across the board, regardless of the mobility mix. For corporate space in the United States the typical range is about 45 – 55 RSF/Day, depending on office sizes and the amount of shared space. If you're a commercial real estate broker or in-house professional, imagine the value you'd bring with a quick and easy method for estimating true real estate requirements for the new workplace.
Start doing it right. Get to know the new rule of thumb. It’s 50 RSF/Day.