A table headed units in structure can sound like a building inventory. In ACS housing tables, however, the categories generally describe housing units according to the size or type of structure that contains them. Reading a count in an apartment building category as a count of buildings can multiply the apparent building inventory and distort a neighborhood description. This guide uses fictional...

A home described as having five rooms does not necessarily have five bedrooms. In Census housing statistics, rooms and bedrooms are separate measures. Occupants per room uses the room count, not simply the number of bedrooms. Confusing these concepts changes the denominator of a housing indicator and can lead to unsupported claims about how a home is used. This guide explains the statistical distinctions...

A chart of reasons for moving can tell a useful housing story, but its wording matters. A reported main reason describes the answer recorded for a move. It does not measure every consideration behind that decision, establish what would have happened under different circumstances, or reveal the preferences of everyone who stayed. Those distinctions are essential when translating national survey findings...

A New York City building search can look incomplete because the researcher stopped in the first system that returned an address. The Department of Buildings directs readers to both the Building Information System, known as BIS, and the DOB NOW Public Portal. The useful task is matching the question and record type to the system that holds it, then preserving the identifiers needed to connect the...

A spreadsheet contains the median rent for every neighborhood. Averaging those medians produces one convenient citywide number. The calculation is easy, but the result is not generally the median rent of the city's households. Each neighborhood median is a summary that has already discarded much of its underlying distribution. Census guidance notes that derived estimates such as medians cannot simply...

Two neighborhoods report renter shares of 20% and 80%. Their simple average is 50%. That average describes the two percentages when each neighborhood receives equal weight. It does not necessarily describe the renter share of all occupied units across the neighborhoods. For that question, the counts behind the shares matter. Census housing tables identify tenure categories and their occupied housing...

A housing report can contain two income figures that look almost interchangeable: median household income and median family income. Replacing one with the other changes the population being summarized. It can also change whose earnings enter a particular income total. Before using either measure to describe a neighborhood, identify the unit of analysis, the people whose income contributes, and the...

A housing dataset may classify a unit as built before 1940 even when its kitchen, windows, and heating equipment were replaced recently. That is not necessarily a contradiction. The ACS year structure built measure concerns original construction, not the latest renovation. Treating it as a record of improvement dates can mislead buyers, renters, researchers, and anyone comparing the condition of housing...

A housing chart published last month shows one number for January. The source now shows a different January number. Before changing the chart, determine what changed: the source estimate, the statistical method, the downloaded series, or your own processing. Those possibilities require different explanations, and treating them all as errors can confuse readers. The Census Bureau publishes preliminary...

Opening a survey microdata file can feel like opening a complete list of households. Each row contains attributes, and counting rows produces an exact number. But that exact row count is a count of records in the file, not automatically an estimate of the population those records represent. Survey weights are essential to understanding the difference. The American Community Survey Public Use Microdata...