A social indicator is a quantitative measure used to evaluate, compare and track the development of various aspects of a society's well-being. These indicators provide information on the living conditions of the population, the quality of public services, access to resources and rights, among other factors that affect people's daily lives.

A social indicator is a summary measure, preferably statistical, referring to the quantity or magnitude of a set of parameters or attributes of a society. It allows you to locate or classify the units of analysis (people, nations, societies, goods, etc.) with respect to the concept or set of variables that are being analyzed.

There are simple indicators and complex indicators. For example, the illiteracy rate and access to drinking water are simple social indicators, since they refer to attributes whose presence or quality level can be verified in a simple and empirical way. The case of indicators such as social class or prestige is different, which require a more complex conceptual framework, as both are a theoretical construction and do not have a concrete empirical equivalence. In the composition of indicators, clear and precise concepts must be present, which do not require great mathematical or statistical development.

The social indicators used in social projects based on a logical framework are specific, explicit and objectively verifiable measures that seek to account for the changes produced by the project,[1]​ in other words, they allow us to specify the way in which the degree of compliance with objectives and results will be verified.[2]​.

The indicators used in social projects, especially if the logical framework is used, are usually quantitative, however it is possible to use qualitative indicators to obtain an approach to the project's achievements[2]​.

These indicators are usually organized into three types: impact, effect and compliance.[1]​.

The impact and effect indicators correspond to the evaluation level, while the compliance indicators correspond to the monitoring level.

The sequence or life of an indicator begins by selecting one or several that represent what you want to investigate. For example, the indicators life expectancy at birth, illiteracy and standard of living (Gross Domestic Product) allow us to estimate Human Development.

The process to define an indicator is as follows:[3]​.

The indicators must meet some criteria to guarantee their validity. Some of them are the following:[4]​.