I would also add why big corporations are staring to build NEW multi-million dollar campuses instead of renovating a lot of these office parks.

I live in Minnesota and United Health Care has done both. they've bought newer buildings that were vacated and just built a huge (72 acres) campus on the outskirts of the city: http://www.bizjournals.com/twincities/print-edition/2011/09/...

Cargill several years ago built a huge new campus at an abandoned Super Value production plant:

http://www.opus-group.com/OurWork/Excelsior-Crossings

Also, I've seen older 1970's corporate buildings demolished and there's an area in a nearby suburb where they're trying to rejuvenate the area where nearly all the buildings are empty with a $500 million project plan:

Demolition: http://hillcrestdevelopment.com/pentagon-park-south-tower-de...

Renovation of area buildings: http://hillcrestdevelopment.com/renovation/pentagon-park/

Redevelopment Plan: http://www.startribune.com/edina-aims-at-a-signature-project...

There are a lot of empty old buildings downtown, too. I don't remember seeing any comparative data in the article beyond that employers seem to be reducing space/employee (they are of course also reducing the number of employees). Of course it makes sense to contract toward the center, that has nothing to do with preferences, it's just economic geography 101.

With respect to the particular building mentioned in the article, it is hardly surprising at all that the NIH is contracting its footprint given recent funding history.

Edit: As mentioned by another commenter, it turns out the NIH didn't move things downtown. Instead, it's just opened a brand new campus that's even further away.

The beltway has a vacancy rate of 17.1%, within the city it's 12.3%. Not that different, especially when you consider that DC has an artificially low vacancy rate due to height restrictions.

And anyway, Montgomery County, MD, is an unusual case. There was a lot of speculative building going on there due to rumors that the city of DC was going to put in a subway line through the country (going back to 2003). That dream has evaporated, with current estimates putting the project out to 2030 and later, so you have a lot of speculators left holding the bag.

I would call a 40% difference in vacancy quite significant.

40% of a small number is still a small number. Lightening strikes 100% more men than women.

17% is not a small vacancy rate. It's a fairly high vacancy rate.

I don't know where you are, but in the US that's just about average --http://m.nreionline.com/office/once-again-office-vacancy-rat...