American Community Survey (ACS)
an ongoing survey conducted by the United States Census Bureau. The survey is given to a small percentage of households and used to estimate data for the entire population. While the ACS collects a wide range of useful data about people and housing, sometimes sample sizes are too small to generate accurate estimates for the population. The accuracy of ACS estimates is indicated by their margin of error.
Average
the mean of a dataset, usually used to represent a “typical” value. This is calculated by adding all the values together and dividing by the number of values. Averages can be misleading since a few very high or very low values in a dataset can skew the average. In such cases, the median is usually a better measure of what is typical.
Census
the dataset collected every ten years by the United States Census Bureau which represents a complete sample of people and housing. The first population census was in 1790.
Census Tract
a geographic area which exists for the purpose of reporting data and has boundaries determined by the US Census Bureau. Census tracts generally contain between 2,500 and 8,000 residents with an optimum population of 4,000. Because of they have a target population, census tracts tend to be geographically smaller in more densely populated areas and geographically larger in sparsely populated areas. Census tract boundaries may change slightly every 10 years. Census tracts are within counties, and no census tract spans two counties.
Ecosystem Services
processes that occur within the natural system of the environment (both living and nonliving) which benefit humans. For example, an ecosystem may naturally filter groundwater, which benefits the humans who will eventually use it.
Equity
all individuals, regardless of “markers of difference” including but not limited to race, ethnicity, income, disability, and age, have equal privilege and opportunity to access the basic needs, services, skills and assets required to succeed in life. This includes affordable access to healthy food, adequate and appropriate housing, quality jobs, safe neighborhoods, transportation and mobility options, education, civic engagement, health services, natural areas, and opportunities to participate in arts and cultural activities.
Ethnicity
a descriptor of a group of people sharing a common race, national heritage or cultural background. The US Census Bureau defines race and ethnicity separately, defining ethnicity only as “Hispanic or Latino” or “Not Hispanic or Latino.” According to data from the Census or American Community Survey, “Hispanic or Latino” is not a race (it is an ethnicity), but people of any race can be “Hispanic or Latino.”
Geographic Information System (GIS)
computer software used to gather, store and analyze geographic data, often used to create maps.
Greater Portland Region
Clackamas, Multnomah and Washington Counties in Oregon and Clark County in Washington.
Infrastructure
the basic physical structures which exist in order for built systems to function. Infrastructure can include roads, sidewalks, sewer systems, lighting, power lines, etc.
Margin of Error (MOE)
A statistic expressing the amount of random sampling error in a survey's results. The larger the margin of error, the less faith one should have that the poll's reported results are close to the "true" figures; that is, the figures for the whole population. Margin of error occurs whenever a population is incompletely sampled. The American Community Survey (ACS) estimates are based on data gathered from a sample of the population (approximately 1 in 40 households) rather than the full population. Data based on samples include a range of uncertainty based on the fact that the: 1. Estimates of characteristics from the sample data can differ from those that would be obtained if the entire population were surveyed. 2. Estimates from one subset or sample of the population can differ from those based on a different sample from that same population. Sampling error is related to sample size. Specifically, the larger the sample size, the smaller the uncertainty or sampling error for estimates based on the survey sample. This relationship between sample size and sampling error is the reason that ACS estimates for smaller geographic areas are based on multiple years of data. Combining ACS data from multiple years increases the sample size and in turn reduces the uncertainty or error associated with ACS estimates. All ACS estimates are published with their margins of error (MOE) at the 90 percent confidence level. In other words, we can be 90 percent certain that the range established by the margin of error contains the population value.
Mean
see “Average.”
Median
the middle number in a set of numbers listed from lowest to highest. The median is often a better measure of what is typical in a set of data than the average (or mean) because it is not distorted by a few very low or very high numbers.
Metadata
Information about data. The metadata page on this site provides information about data including the source, methodology and update frequency.
Metro
the regional government for the Oregon portion of the Portland-metro area which oversees land use planning, habitat protection, garbage and recycling, regional data tracking and analysis, some transportation responsibilities, and some parks and event centers. Metro serves cities in Clackamas, Multnomah, and Washington counties and is led by a directly-elected Metro Council.
Metropolitan Statistical Area (MSA)
a geographic area defined by the US Census Bureau for data reporting purposes, generally with a dense urban core and including all surrounding areas which are closely economically connected to the core. Geographic boundaries for MSAs may change every ten years. The Portland-Vancouver-Hillsboro MSA for the 2010 Census includes Clackamas, Columbia, Multnomah, and Washington counties in Oregon, and Clark and Skamania Counties in Washington. This is different than the geographic area of the Greater Portland Region which includes neither Columbia nor Skamania Counties.
Morbidity
the extent of disease or illness in a population.
Per Capita
per person average.
Race
a descriptor of a group of people sharing a common ethnicity, national heritage, or cultural background. The US Census Bureau defines race and ethnicity separately, defining “Hispanic or Latino” as an ethnicity but not a race. Over time, the race classifications included in the Census have changed. Data from the 2010 Census generally reports seven race categories: “White,” “Black or African American,” “American Indian and Alaska Native,” “Asian,” “Native Hawaiian and Other Pacific Islander,” “Some Other Race,” and “Two or More Races.”
Rate
a number which is “out of” a larger specified data set. For example, incarcerated juveniles “out of” all juveniles and seven “per” 1,000 people are both rates.
Trend
a direction of change determined by examining data over time.
Urban Growth Boundary
a legal border separating urban and rural areas. Land use in both the Oregon and Washington portions of the greater Portland region are influenced by the location of urban growth boundaries. The purpose of the boundaries is to protect rural and natural lands from development, keep urban areas dense and vibrant and prevent the negative impacts of urban sprawl.
Watershed
a geographic area with boundaries which are defined by the flow of water into a single body of water (river, tributary, or lake). Rain falling in any part of a watershed will eventually flow into the specific water body which defines the watershed.
Weave (or WEAVE)
Web-based Analysis and Visualization Environment. This is an open source platform that allows for creation and display of interactive data visualizations including charts, tables, and maps. Greater Portland Pulse uses WEAVE to display interactive visualizations of indicator data. Members of the public can also use WEAVE and the data provided by Greater Portland Pulse to create custom data visualizations.