As Samuel Clemens said, there are three types of lies: lies, damn lies, and statistics. The difference between the census estimate and the PRC estimate lies in the methodology. The Census uses a housing-based method, looking at new construction, including permits and mobile home placements; based on that construction, it uses its data for estimating household population. The Census estimates are than checked against "other analysis" (which, I'd guess is stuff like PRC data). PRC, on the other hand, looks at natural growth (births and deaths) as well as migration; PRC's data is tax exemptions, school enrollment, Medicare enrollment, and the like. Its estimates are then checked against housing models.

Why the difference? In my uneducated and completely spectulative opinion ... I guess the following:
(1) The apartment household size is smaller than the single-family residence household size; when the Census creates its estimate, Portland's family-apartment communities are under-represented (i.e. the Pearl is not just singles and DINKs).
(2) Portland houses are being sub-divided into multiple residences very quickly, but these are not permitted new construction. Friend of mine just divided his basement into two finished bedrooms to rent out; this growth probably isn't represented.

Overall, I'd wager that PRC is probably closer to the "real" number because it looks at more "local" factors that represent real individuals (enrollment) rather than places for individuals.

Sorry: cites. Census methodology is explained here: http://www.census.gov/popest/topics/methodology/2007_su_meth.html

PRC methodolgy is in the report on its page 4, pdf page 6.

Shall we really trust the data of a Bush era government bureau? Would they falsify data from a blue state thus affecting its funding and districting? Nah, that would never happen!

there is no "real" number. everybody isn't counted. both methods use a significant amount of statistical inference to determine how many people live here.

so, either number is both valid and invalid.

if i had to pick one, i'd go with the PSU number.

I don't know how long PRC had been doing what it does. However, if it's been around a while one could check PRC's estimates against the decennial Census. That would provide some indication of how much the Census Bureau and the PRC "true up."

Shall we really trust the data of a Bush era government bureau?

Or should we trust the PSU school of "urban planning," which would have an enormous incentive to show that the city's population is increasing due to the supposed success of its eco-density policies?

It's a tossup.

PRC has been making such estimates since at least the early 1970's. Their offices were across the hall from me for my first 10 or so years at PSU. Whether their estimates are more or less reliable than the Census Bureau depends on what methodology you choose. The PRC is solely about Oregon and so there is some incentive to provide fairly accurate estimates based on many factors. I know that their data feed to the US Census Bureau in decentennial years. I don't know about the interdecade estimates.

by the census bureau numbers, Portland lost almost 6,000 residents between 2003 and 2004. I'm thinking Washington DC's numbers are more likely wrong than PSU's.

"As Samuel Clemens said, there are three types of lies: lies, damn lies, and statistics."

Who was by the way quoting British Prime Minister, Benjamin Disraeli.

Yes I know picky, picky, picky.

And to stay on point I am more inclined to agree with the PSU numbers. But then I am biased, I got one of my degrees there.

Well sh t you just tipped off the city on how they can lower the debt per capita.

All they need do is pad the population count a hundred thousand more and wa la,
there's room for more borrowing.

Wow! That's almost exactly what they've been doing with Urban Renewal borrowing.
Padding the revenue projections to allow greater borrowing capacity.

Or should we trust the PSU school of "urban planning," which would have an enormous incentive to show that the city's population is increasing due to the supposed success of its eco-density policies?

It's a tossup.

Good point, Jack. I guess John Q Statistic can get so dazzled by the sheer magnitude of Bush & Friend's corruption that its easy to forget the old everyday "smalltime" shenanigans. Seems almost quaint...almost.

It's all pretty sketchy.

Yeah, Ken pretty much nails the discrepancy.

In 2003-2004, PSU says we grew by 5k residents. But the Census Bureau says we shrank by 6k residents.

In every other year, PSU and the Census basically agree on the amount of growth.

Obviously, something unique happened in 2003-2004 that caused one methodology to go one way - and the other to go the other way.

It'd sure be interesting to know what that was.

Here are the rest of the Census numbers (all July 1) since the last count:

2002 - 539,835
2001 - 535,624
2000 - 529,948

Here are Portland State's:

2002 - 538,180
2001 - 536,240
2000 - 531,600

The official Census number as of 4/1/00 was 529,121.

It appears that PSU has consistently been over the Census, ever since the last actual counting.

So my question is - how come Sam Adams (and others) keep talking about how the city will need to absorb 1,000,000 more people (or 500,000 or whatever the SCARY number is - my memory fails me at the moment) when we're seeing population growth of around 5,000 per year?

There are different methodologies used to count the homeless in a census. One is actual enumeration; another is a statistical estimate based on sampling; still another is to build in a fudge factor and use it. Why doesn't someone just ask PSU for an explanation. I'm sure they'd be happy to oblige.

PSU is surely overstating their numbers...anything to inflate the numbers to make it appear their forced density goals are successful.

Portland has become a socialist city, like SFO, now way in hell I would move back. Many others...(except the homeless looking for handouts)...share the same view.

Many, including myself will move out, to a more tax friendly state...Nevada, Utah, Wyoming will see great growth.

"Nevada, Utah, Wyoming will see great growth."

I ain't complainin...goodbye, so long...more beautiful Oregon for me to enjoy.