Glossary of Terms Aggregation - The level at which data of the same type are gathered or grouped together. For instance, specific address data can be grouped together and displayed in blocks, census tracts, etc. Analysis - The process of identifying a question or issue to be addressed, investigating multiple possible solutions, interpreting the results of that investigation, and possibly making a recommendation. Average - The result obtained by dividing the sum total of a set or group of numbers by the total number in that group. Use caution when using this type of calculation, as high numbers in a set or very low numbers in the set skew the average number and distort the picture of what the indicator is supposed to express. Baseline - The average rate or level of some variable at a point in time. It is generally understood that the baseline is the "before" measure that will be used for future comparison. Thus, the baseline is the measure prior to an intervention or strategy, and can be used as the starting point for tracking a trend. Benchmark - A point of reference or a standard against which measurements can be compared. Census - The Decennial Census is the census (or complete enumeration) of population and housing, taken in each year ending in zero. Article 1, section 2 of the U.S. Constitution requires that a census be taken every 10 years for the purpose of apportioning the U.S. House of Representatives. The first census of population was taken in 1790. The Census Bureau first conducted the census of housing in 1940. Census tract - A small, relatively permanent statistical subdivision of a county or statistically equivalent entity delineated for statistical data presentation purposes. Census tracts generally contain between 2,500 and 8,000 people, with an optimum size of 4,000 people. Census tracts vary in actual size because they are based on the number of people in the area, not the number of miles. Census tract boundaries are delineated with the intention of being stable over many decades, so they generally follow relatively permanent visible features. However, census tract boundaries always follow governmental unit boundaries: the boundary of a state or county is always a census tract boundary.  Data - The purest definition of data is "information collected." Data are often thought of as statistical or quantitative, but they may take other forms-such as transcripts of interviews or videotapes of social interactions. Data are often coded-or quantified-to make them easier to analyze. Data then becomes statistical evidence from which conclusions can be inferred Database - A collection of interrelated information, managed and stored as a unit on a disk or hard drive. Data set - A collection of related data items. Disclaimer - A statement used to exclude a business or entity from liability. In cases regarding data, disclaimers are often used to express to the user that not all the data may be reliable and accurate, and that the data provider is not responsible or liable for any misuse of the data or any related actions. Geographic data - Information that pertains to a specific point or area on a surface of the globe; for example, streets, census tracts, neighborhoods, zip codes, etc. Geographic information system (GIS) - An organized collection of computer hardware, software, geographic data, and personnel designed to efficiently capture, store, update, manipulate, analyze, and display a number of data items on maps. Indicator - A measure that helps to quantify, express, or “indicate” the achievement and/or progress toward an outcome or goal. The indicator is the statistic or measure (or set of measures) that helps describe the social/physical condition. The indicator may be used to measure achievement or progress toward an outcome but in its purest definition it is the measure alone. It answers the question: “What will indicate to us we are reaching the goal?” Legend - The reference area on a map that lists and explains the colors, symbols, area polygons, shadings, and annotation used on the map. The legend often includes the scale, origin, orientation, and other map information. Measurement - A determination of the extent or dimension of something by a standard. Rates, percentages, numbers, etc.,  are all measurements. Median - The number that falls in the middle between the highest number and the lowest number in a series of numbers. The median is different than an average, which considers all the numbers in the calculation. With an average, high numbers in a set or very low numbers in the set skew the resulting number and distort the picture of what the indicator is supposed to express. Outcome - The desired change (overall result) in behavior or condition you hope to achieve. Examples: well-being for children, adults, families or communities, and/or the environment (e.g. children born healthy, children succeeding in school, economically sufficient families, clean environment). Outcome indicator - An indicator of the desired condition or result. Outcome indicators (sometimes called outcome measures) are used to understand the progress toward the overall outcome. Output - See Performance Indicator. Percent - A given part of a whole, meaning that 100% of something is all of it. 50% of something is half of that whole. Performance indicator - (sometimes called a Process or Program indicator. Most commonly known as an “Output”.) An indicator used to gauge effectiveness of an agency or program service delivery. For example, an indicator of how well an agency or program is providing a service to customers (e.g. citizens - police response time, staff turnover rate, percentage of customers served in their own language, percentage of clients off alcohol and drugs). Qualitative data - Data that is non-numerical, or not easily reduced to numbers, collected for the purpose of discovering underlying meanings and patterns of relationships. For instance, what people think about their own neighborhoods, or how neighbors feel about their neighborhood, is qualitative data. Quantitative data - Numerical information that can be summarized in statistics for analysis purposes. Rate - A calculation of the amount or degree of something in relation to units of something else. For example, the number of juveniles ages 10-17 arrested per 1000 juveniles is the juvenile arrest rate. Static map - A map that is non-interactive. Statistics - Numerical summaries of data. Descriptive statistics are procedures for summarizing, organizing, graphing, and, in general, describing quantitative information. Inferential statistics are statistical techniques that allow you to draw conclusions from the data. Trend - A direction demonstrated through observation of data over time.  Trend analysis - (also known as time series analysis). Tracks a variable over time and uses statistical techniques to determine whether any changes in the variable are occurring by chance or because of an intervention. The time series analysis adjusts the trend line to account for seasonal changes and other influences. Glossary adapted from: The Community Indicators Handbook, Redefining Progress, 1997  The Practice of Social Research, Earl Babbie, sixth edition, 1992 Baltimore Neighborhood Vital Signs Project: Community Focus Group Facilitator Training, Kate Besleme, 2001  Assistance from Tracey Rutnik, director of Evaluation at the Association of Baltimore Area Grantmakers  U.S. Census website (http://www.census.gov) for definitions of census data BNIA (Baltimore Neighborhood Indicators Alliance) data partners for definitions of the data provided.  BNIA website:  http://www.bnia.org. Mapping Your Community, U.S. Department of Housing and Urban Development, 1997  ESRI (Environmental Systems Research Institute) website (http://www.esri.com) for mapping terms State Department of Assessment and Taxation (housing definitions) Merriam-Webster English on-line dictionary (http://www.m-w.com/dictionary.htm)