Vitalnet Health Statistics - Glossary

Age-adjusted death rate - Deaths per 100,000 population, adjusted to a standard population (such as US 1940 or US 2000), by the direct method. Age-adjusted rates are often better for making comparisons than unadjusted rates, because they adjust for differences in age distribution between populations. An age-adjusted rate is a summary measure. Besides calculating overall age-adjusted rates, it is also recommended to compare age-specific rates.

Age-adjustment standard - A standard population for calculating an age-adjusted death rate. The 1940 and 2000 US Census population are the most common standards.

Area set - One or more areas combined.

ASCII file - A text file, with only alphabetical, numerical, and punctuation characters, like you would see in normal text. Vitalnet can produce output in ASCII format.

Bar graphs - A section of a Vitalnet table. Gives a useful graphical representation of the data. May be omitted from the output table.

Cause of death - Any condition which leads to or contributes to death and is classifiable according to the International Classification of Diseases (ICD) system.

CDC - Centers for Disease Control and Prevention. US federal health agency.

Cell - A space for a single numerical result in a table, at a row-column intersection.

Cell suppression - An asterisk "*" is placed in cells with fewer deaths than a limit set by the user. Row / column totals with exactly one suppressed cell in the row / column are also suppressed. If more than one cell in the row / column is suppressed, the row / column total is displayed.

Columns - Vertical groupings of data in a Vitalnet table, such as a column for each race group.

Confidence interval (confidence limits) - A range of values within which the true value of a variable is thought to lie, with a specified level of confidence. For a result of 23.5, a confidence interval might be (23.1-23.9). The smaller the interval, the more reliable the result. If the 95% confidence intervals do not overlap, there is a statistically significant difference. Vitalnet uses several methods to calculate confidence intervals. The output table documents which method was used.

Confidence level - The likelihood that the true value of a variable is within a confidence interval. For example, for confidence intervals at the 95% level, we are statistically 95% certain that the actual value of the variable is within the interval.

Councils of Government (COG's) - Groupings of Texas counties. There are 24 COG's.

CSV format - Also called comma-separated-value format. A type of computer output that is readily imported into other software, especially spreadsheet software. Each output item is separated by a comma from surrounding items, and each output text item is surrounded by "double quotes". Vitalnet produces CSV output. A comma-separated-value file has "csv" extension.

Data mining - Finding unexpected relationships in a data set. Similar to exploratory data analysis. Vitalnet is excellent at data mining. Of course, keep in mind that the more you look, the more unusual events you will find, just by chance.

Data warehouse - Software system, such as Vitalnet, making large complex databases readily available for querying and analysis.

dBASE III format - A widely used file format derived from the database software of the same name. Files in this format may be readily imported into almost any data analysis, graphing, mapping, or other presentation software. Has dbf extension. Suppressed cells are represented as the number "-1". Vitalnet produces dBASE III output.

Death rate - Deaths per 100,000 population. May be used to compare the burden of disease between different groups. Also called crude death rate.

Denominator - The number on the bottom of a fraction. Population data are often referred to as "denominator data", as they are used as denominators to calculate population-based rates.

E codes - "External" causes of death such as injuries and poisonings. E codes range from ICD 800 to ICD 999.

Export - Produce output that can be read into other computer programs. Vitalnet produces ASCII text, comma-separated-value (csv extension), HTML (htm extension), and dBASE III (dbf extension) files for export.

Filter variable - A variable solely used to filter which records are included in the output. For example, for a single table with race rows and sex columns, age is a filter variable.

Footer - Last part of a Vitalnet table. Lists other details of the analysis, such as the date and time produced, and the data sources. Each table is assigned a unique ID, listed in the footer, to assist you in keeping track of and organizing analyses.

Header - First part of a Vitalnet table. Lists basic parameters you selected to define the table, such as years analyzed.

ICD - International Classification of Diseases. A widely used system of classifying diseases and injuries. Each disease or set of diseases has an ICD code or ICD group assigned to it. Vitalnet uses the ICD-9 system, which has been in use since 1979, and the ICD-10 system, which started with 1999 mortality data.

ICD-9 code - A single ICD number representing a single disease or injury (for example, ICD 250 for diabetes). Note - ICD codes for HIV / AIDS first came into use in 1987.

ICD-9 group - A range of continuous ICD-9 codes (for example, ICD 10-18 for tuberculosis).

ICD-9 set - One or more ICD-9 groups or codes combined, for example ICD 174 (female breast cancer) and ICD 180 (cervical cancer).

Import - Read information into a computer program. ASCII text, CSV files, HTML, and dBASE III files from Vitalnet are easily imported into word processing, spreadsheet, data analysis, mapping, graphing, and other presentation software programs.

Leading causes for ICD-9 - The ten causes of death with the highest number of deaths, out of a standard National Center for Health Statistics list of 38 rankable causes. Vitalnet makes it easy to select and rank the 38 cause list.

Least-squares - A standard method for fitting the best straight line to a set of points. Produces a 1 -intercept and a slope defining the least-squares line.

Mean age of death - If the ages of death were 50, 51, and 58, the mean age of death is (50 + 51 + 58) / 3 = 53

Multiple age groups - One age group for each row or column of a table. Example: Birth-19, 20-39, 40-59, 60-99+.

Multiple cause mortality data - Data which include all causes of death listed on the death certificate. Contrast with underlying cause mortality data.

Multiple causes of death - All diseases or injuries which led directly to death, or all circumstances of the accident or violence which produced the fatal injury.

NCHS - National Center for Health Statistics. US health statistics agency. Part of the CDC.

PHR - Public Health Region. Groupings of Texas counties. There are 11 PHRs.

Place of occurrence mortality data - Data compiled by the location where the death occurred, without regard to the place of residence of the deceased. Vitalnet does not currently analyze for place of occurrence.

Place of residence mortality data - Data compiled by the usual place of residence of the deceased, without regard to the location where the death occurred. Vitalnet analyzes mortality data by place of residence.

Population - The number of people living in an area.

Primary Statistic - The basic type of numerical result displayed in a table, chart, or map. For example, death rate.

Public Health Regions (PHR) - Groupings of Texas counties. There are 11 Public Health Regions.

Rows - Horizontal lines in a Vitalnet table, such as a row for each race group.

Row sort settings - Vitalnet rows may be sorted in ascending or descending order.

Set - A combination of one or more things. For example, several areas may be combined into an area set.

Single age group - Only one age group (30-49, for example) is selected. A single age group is used for tables that do not have age columns or age rows.

Standardized mortality ratio (SMR) - The ratio of the expected number of deaths in a population to the observed number of deaths. The expected number of deaths is derived from applying a standard set of rates (usually state or national rates) to the population. SMRs are useful for assessing whether the mortality in a population is higher than expected.

Statistic - See "Primary Statistic".

Table - A set of results produced by Vitalnet. A table has several parts:

1. Header - lists basic analysis settings
2. Data section - numerical results
3. Horizontal bar graphs - graphical representation of the data
4. Footer - lists other analysis settings

Underlying cause - The disease or injury that initiated the train of events leading directly to death, or the circumstances of the accident or violence which produced the fatal injury. A single underlying cause is assigned to each death.

Underlying cause mortality data - Data which include only the underlying cause of death listed on the death certificate. Contrast with multiple cause mortality data.

UNIX - A widely used computer operating system. Vitalnet can run on UNIX, either remotely, locally, or by client-server.

Unknown Values - Unknowns are automatically inserted into a Vitalnet table. For example, a separate row (or column) for unknown race. The rate is assigned as zero for an unknown category, since there is no population denominator to use. Some fields, such as sex for certain data sets, are never unknown, so unknowns are left off the table. When, such as for age-adjusted rates, the unknown variable (age) is different from the rows or columns, the number of unknowns for age is shown below the table.

Windows - A widely used set of PC operating systems, including Windows 3.1, 95, 98, NT, 2000, and XP. Vitalnet will run under any version of Windows.

World Wide Web (WWW) - A widely used part of the internet that may be easily accessed with a web browser. Vitalnet runs on the WWW.

Years of potential life lost (YPLL) - Sum of the years of life lost by persons who suffered early deaths. Early death is usually defined as death occurring before the age of 65 (the YPLL age limit). For example, death at age 40 (40.5) results in 24.5 YPLL to age 65. YPLL is a widely used measure of premature mortality.

YPLL age limit - The age used for calculating YPLL. The most common age limit is 65, but other age limits may be selected from within Vitalnet.

YPLL rate - YPLL per 100,000 population in the appropriate age category. For example, the YPLL rate up to age 65 is calculated as follows: (YPLL up to age 65) / (population for age group 0-64). YPLL rate is not commonly used.