applies the techniques of econometrics in their forecasting process. Typical steps may include: Scope: Key economic variables and topics for forecast commentary are determined based on the needs of the forecast audience. Literature review: Commentary from sources with summary-level perspective, such as the IMF, OECD, U.S. Federal Reserve, and CBO helps with identifying key economic trends, issues and risks. Such commentary can also help the forecaster with their own assumptions while also giving them other forecasts to compare against. Obtain data inputs: Historical data is gathered on key economic variables. This data is contained in print as well as electronic sources such as the FRED database or Eurostat, which allow users to query historical values for variables of interest. Determine historical relationships: Historical data is used to determine the relationships between one or more independent variables and the dependent variable under study, often by using regression analysis. Model: Historical data inputs and assumptions are used to develop an econometric model. Models typically apply a computation to a series of inputs to generate an economic forecast for one or more variables. Report: The outputs of the model are included in reports that typically include information graphics and commentary to help the reader understand the forecast. Forecasters may use computational general equilibrium models or dynamic stochastic general equilibrium models. The latter are often used by central banks. Methods of forecasting include Econometric models, Consensus forecasts, Economic base analysis, Shift-share analysis, Input-output model and the Grinold and Kroner Model. See also Land use forecasting, Reference class forecasting, Transportation planning and Calculating Demand Forecast Accuracy. The World Bank provides a means for individuals and organizations to run their own simulations and forecasts using its iSimulate platform. Issues in forecasting Forecast accuracy There are many studies on the subject of forecast accuracy. Accuracy is one of the main, if not the main, criteria used to judge forecast quality. Some of the references below relate to academic studies of forecast accuracy. Forecasting performance appears to be time-dependent, where some exogenous events affect forecast quality. As expert forecasts are generally better than market-based forecasts, forecast performance depends on several factors: model, political economy (terrorism), financial stability etc. In early 2014 the OECD carried out a self-analysis of its projections. "The OECD also found that it was too optimistic for countries that were most open to trade and foreign finance, that had the most tightly regulated markets and