ACS Data Users Group

Hello,

I was using the creator to get a table showing the age structures were built for the top 15 metro areas ("Year Built" under "Structural" variable) for 2019.

I wanted to see if anyone could tell me whether the estimates of the number of structures built in year "x" are raw estimates from the public use data, or if there were any sort of weights used in creating the summary tables.

For example, (after cleaning the data), here's a row of estimates for Boston of the number of structures built in each year range.

What is the correct way to interpret the estimate for say, the 136.4 buildings reported being built in 2000-2009? Is it simply the number of responses of "2000" under the YRBUILT question in the survey? Also, does 136.4 mean 136.4 structures? Or does it mean something like 13640 structures?

I hope my questions make sense. Thank you very much for any and all input.

A tip: 'year built' data has profound distortions: you won't find enough Boston structures 'built' in the 1700s even though the structures still exist. Even where the data comes from a tax assessor, 'year' usually means the EFFECTIVE age/date of a building, not its actual date of initial construction. Also, Since construction records weren't kept until long after cities were built,, assessors or others built records from utility hook up dates and other imperfect sources. If date data is self-reported by owners of structures , owners can be 100s of years wrong...