Univariate Time Series | Vose Software

Univariate Time Series

See also: Time series introduction, Time series in ModelRisk, Vose Wilkie Models, Vose Multivariate Time Series window

Introduction

A time series is a stochastic forecast of a variable over time.

Often, we want to predict what these values will be for future years based on data for the past and/or theoretical considerations. This is called a time series forecast.

The output of a Time Series forecast in ModelRisk is a one-dimensional array of randomly generated values. These represent predictions made by the time series forecast, based on the mathematical basis behind it, past data and/or the time series' parameters.

For an overview of the time series available in ModelRisk, see the Time series in ModelRisk topic.

You can read more about the theory behind time series here.

To see the output functions of this window, click here.

Window elements

Time series parameters

In the Time series parameters section, you can choose between a number of different Time Series models:

These are explained one by one in the Time series in ModelRisk topic.

Each of these takes a certain set of parameters, which can be inserted manually by typing in the appropriate field, or dynamically link to a value in a spreadsheet cell.

Window elements

Options

In the Options area, a particularly interesting field is Number of lines: as a Time Series forecast is uncertain, many scenarios are possible. By default, only one is generated and shown in the graph pane. If you set this field to a higher number you will see a set of different scenarios generated and presented.

For easy comparison, you can also display historical data from your spreadsheet together with the modeled forecast.

Also, the output location (i.e. a one-dimensional array of spreadsheet cells) can be selected. This can be either typed directly, or selected from the active worksheet.

Time Series graph


Time Series graphs from the Time Series window

In the middle pane, a graph for the generated Time Series model is shown. The lines represent randomly generated Time Series forecasts.

By default, only one line is shown in blue. This number can be increased by changing the Number of lines field mentioned above.

For explanations about other fields, buttons, graphs and summary statistics tables in this window, see Common elements of ModelRisk windows.

Useful tips and tricks

See also: Graphics, workflow and error handling in ModelRisk

Using View Function to return to a window

The output of ModelRisk windows always corresponds to VoseFunctions (the functions ModelRisk adds to Excel) being entered into one or more spreadsheet cells.

You can always re-open the window for a ModelRisk function that is in a spreadsheet cell by using View Function. Select the spreadsheet cell and then select View Function from the ModelRisk menu/toolbar/ribbon.

 

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