Terms Used in this Publication

SAS® Visual Forecasting: User’s Guide

accumulation

either of two processes that are used to convert a time series. (1) Accumulation converts a time series that has no fixed interval into a time series that does have a fixed interval (such as hourly or monthly). (2) Accumulation converts a time series that has a fixed interval into a time series with a lower frequency time interval (such as hourly into daily). Accumulation combines data within the same time interval into a summary value for that time period.

aggregation

the process of combining more than one time series to form a single series within the same time interval. For example, data can be combined into a total or an average.

confidence limits

the upper and lower values of a (usually 95%) confidence interval. In repeated sampling, approximately (1-alpha) 100% of the resulting intervals would contain the true value of the parameter that the interval estimates (where alpha is the confidence level associated with the interval).

disaggregation method

a method that specifies how the forecasts in the lower level of the hierarchy are reconciled when the reconciliation method is top-down or middle-out. The disaggregation method can reconcile the forecasts in either of the following ways: (1) by using the proportion that each lower-level forecast contributes to the higher-level forecast; or (2) by splitting equally the difference between the higher-level forecast and the lower-level forecasts.

dummy variable

a numeric variable with a value of either 1 or 0 that is used to indicate whether or not unusual events occur. The variable takes the value of 1 during the event and 0 otherwise.

event

an incident that disrupts the normal flow of any process that generates the time series. Examples of events are holidays, retail promotions, and natural disasters.

FAR file

an archive file that has been exported from a SAS Forecast Server project. The file contains the data definitions, properties, events, and other resources needed to run the project in another environment. The other environment could be a SAS Forecast Server or a SAS Visual Forecasting deployment.

filter

a set of specified criteria that are applied to data in order to identify the subset of data for a subsequent operation, such as continued processing.

forecast

a numerical prediction of a future value for a specified time period for each unique combination of BY variable values

holdout sample

the number of periods of the most recent data that should be excluded from the parameter estimation. The holdout sample can be used to evaluate the forecasting performance of a candidate model.

horizon

the number of intervals into the future, beyond a base date, for which analyses and predictions are made.

model selection criterion

the statistic of fit that is used for forecast model selection.

override conflict

a condition that occurs when the value of one locked override is incompatible with the value of another locked override in the same branch of the hierarchy. Override conflicts that are not resolved prior to reconciliation can result in unreconciled nodes.

out-of-sample region

the number of time periods before the end of the data that are removed when fitting models. After model selection, forecasts are generated in the out-of-sample region and then compared to the actual data to determine accuracy.

pluggable model (pluggable models)

a modeling node in SAS Model Studio that contains code that can be edited and saved by the user.

project hierarchy

the order of the variables that you have assigned to the BY variables role. An example of a hierarchy is Region > Product Category > Product Line.

promotion

the process of copying selected metadata and associated content within or between planned deployments of SAS software that could run different software releases. Methods of promotion include import and export processes, as well as explicit copies between two servers. This process is repeatable for a particular deployment.

reconciliation method

the method that specifies the level in the hierarchy where the process of reconciliation starts. The following reconciliation methods are available: bottom-up method, middle-out method, and top-down method.

seasonality

a regular change in time series data values that occurs at the same point in each time cycle.

statistic of fit

a statistical value that is used to evaluate how well a forecasting model fits the historical series by comparing the actual data to the predicted values.

time series

an aggregation of transactional data into specified time intervals and sorted according to unique combinations of the default attributes (BY variables)

top-down method of reconciliation

a reconciliation method that uses the forecasts at the highest level of the hierarchy to adjust the forecasts for the lower levels.

transactional data

timestamped data collected over time at no particular frequency. Some examples of transactional data are point-of-sale data, inventory data, call center data, and trading data.

unlocked override

a user-supplied value for a forecast that acts as a guideline for the final forecast value. The final forecast for the level reflects the value of the unlocked override, but the final forecast and the unlocked override are often not identical. Because these overrides can be overridden when the hierarchy is reconciled, unlocked overrides do not generate override conflicts.

variable label

descriptive text that is associated with a variable, and that can be printed in the output by certain procedures. By default, this text is the name of a variable or of a label previously assigned with the LABEL= option. There is a 256 character limit for variable labels.