Economic data are usually numerical time-series i.e. sets of data (covering periods of time) for part or all of a single economy or the international economy. When they are time-series the data sets are usually monthly but can be quarterly and annual. The data may be adjusted in various ways (for ease of further analysis), most commonly adjusted or unadjusted for seasonal fluctuations.
Economic data may also describe functions or inter-relationships between variables [where the inter-relationships may be theoretical (e.g. a production function) rather than factual], and they may describe a static as opposed to a dynamic relationship (e.g. an input-output matrix or a foreign exchange correlation matrix as opposed to e.g. a series showing changes of automobile output over time).
There are thousands of data sets, covering e.g. the major components of Gross National Product, Gross National Expenditure, Gross National Income, and a whole panoply of series including output, orders, trade, confidence, prices and financial series (e.g. money and interest rates). At the international level there are many series including international trade, international financial flows, direct investment flows (between countries) and exchange rates.
Within a country the data series are usually produced by one or more statistical organisations e.g. a government or quasi-government organisation and/or the Central Bank. There are several international bodies and firms that produce international statistics e.g. the International Monetary Fund and the Bank for International Settlements.
There are many methods available for analysing the data produced e.g. time-series analysis using multiple regression, Box-Jenkins analysis, seasonality analysis. Analysis may be univariate (forecasting from one series) or multivariate (forecasting from several series). Economists, econometricians and financial experts build what can be very complex models that incorporate raw economic data, adjusted economic data, and relationships that they have estimated, to model economic developments. These models may be partial aimed at examining particular parts of an economy or economies, or they may cover a whole economic system and forecast e.g. demand, prices and employment.