This section is intended to assist the reader in following the basic structure of the Digest tables and to provide a legend for some of the common symbols and indexes used throughout the book. Unless otherwise noted, all data are for the 50 states and the District of Columbia. Changes in survey instruments sometimes mean that data for specific categories are not available in a consistent manner over the entire reporting period. Because of these survey limitations, data for these specific categories may be noted as included with other categories where applicable.
The tables in this edition of the Digest include the most recent data available at the time the report was prepared. If no new data were available for a particular table, the table may be repeated without change from the previous edition.
Title Describes the table content concisely. (Tables may not include data for all years implied in table titles. When this is the case, the title will include the term "Selected years.")
Unit indicator Informs the reader of the measurement unit in the table—"In thousands," "In millions of dollars," etc. Noted below the title unless several units are used, in which case the unit indicators are generally given in the spanner or individual column heads.
Spanner Describes a group of two or more columns.
Column head Describes a specific column.
Stub Describes a row or a group of rows. Each stub row is followed by a number of dots (leaders).
Field The area of the table which contains the data elements.
Special notes Symbols used to indicate why data do not appear in designated cell.
† Not applicable.
# Rounds to zero.
! Interpret data with caution.
‡ Reporting standards not met.
Footnote Describes a unique circumstance relating to a specific item within the table. Following are two typical examples:
Estimated Based on available information from a subset of the population of interest.
Projected Calculated from a forecasting model based on historical information.
Note Furnishes general information that relates to the entire table.
Source The document or reference from which the data are drawn. This note may also include the organizational unit responsible for preparing the data.
The Digest most often uses the Consumer Price Index to compare purchasing power over time.
To compute a price index, a base year or period is selected. The base-year price is then designated as the base or reference price to which the prices for other years or periods are related.
A method of expressing the price relationship is:
|Index number =||Price of a set of one or more items for related year||x 100|
|Price of the same set of items for base year|
When 100 is subtracted from the index number, the result equals the percent change in price from the base year.Current and constant dollars are used in a number of tables to express finance data. Unless otherwise noted, all figures are in current dollars, not adjusted for inflation. Constant dollars provide a measure of the impact of inflation on the current dollars.
Current dollar figures reflect actual prices or costs prevailing during the specified year(s).Constant dollar figures attempt to remove the effects of price changes (inflation) from statistical series reported in dollar terms.
The constant dollar value for an item is derived by dividing the base-year price index (for example, the Consumer Price Index for 1999) by the price index for the year of data to be adjusted and multiplying by the price of item to be adjusted. The result is an adjusted dollar value as it would presumably exist if prices were the same as the base year—in other words, as if the dollar had constant purchasing power. Any changes in the constant dollar amounts would reflect only changes in the real values.
In the 2011 edition of the Digest, the following 23 tables include finance data that are adjusted to school year 2009–10 dollars: tables 29, 35, 79, 83, 84, 90, 180, 183, 184, 191, 194, 195, 271, 277, 349, 352, 366, 370, 372, 377, 379, 381, and 434. Data adjusted to calendar year 2010 dollars appear in tables 25, 395, 404, and 429. Table 384 includes adjustments to fiscal year (FY) 2011 dollars.