Definition

1. Noun:
   • A statistical indicator: An index number is a numerical value, often expressed as a ratio, that is calculated from a set of observed data points. Its primary function is to measure and reveal relative changes in a variable over time or across different conditions, using a specific base point (like a base year) for comparison.

Usage

• General Use: An index number simplifies complex data into a single, comparable figure to track trends, such as inflation, economic activity, or stock market performance.
  • Economists use the Consumer Price Index as an index number to measure changes in the cost of living over time.
  • The index number for industrial production showed a significant increase compared to last quarter.

Advanced Usage

• Base-Weighted Index: An index number where the quantities from a base period are used as weights.
  • The Laspeyres price index is a common type of base-weighted index number.
• Chain Index: A series of index numbers where each period is compared to the immediately preceding one.
  • Analysts preferred the chain index number for its ability to reflect recent consumption patterns more accurately.

Variants and Related Words

• Index (noun): Often used synonymously with "index number" in contexts like financial or economic indices.
  • The Dow Jones Index is a well-known stock market indicator.
• Indicator (noun): A broader term for a statistic that provides information about trends.
• Ratio (noun): A relationship between two numbers, which is a fundamental component of many index numbers.

Synonyms

• Statistical measure
• Economic indicator
• Relative number
• Composite measure

Related Phrases

• Price index number: An index number specifically designed to measure changes in price levels.
  • The government publishes a monthly consumer price index number.
• Quantity index number: An index number that measures changes in physical volume or quantity.
• Index number problem: A theoretical issue in economics concerning the choice of formula for calculating index numbers.

Noun

1. a number or ratio (a value on a scale of measurement) derived from a series of observed facts; can reveal relative changes as a function of time