Introduction
The Regression Activity allows you to view correlations on a Site, view the CuSUM and set targets based on the CuSUM and Regression. This activity is not available from the main Activity Menu; it is only available via right click of a Site or through the Site Overview activity.
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Navigation
Click on the Site in the Site Overview Activity
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Alternatively, right-click on a Site and select Regression from the menu
Regression Correlations
On entry to the Regression function, a screen will be displayed which shows all existing Regression Correlations that have been created.
From here, it is possible to view and work with these existing correlations. Alternatively, new correlations can be created by either manually by selecting 
or by letting the system automatically discover potential correlations by selecting 
. More details are provided below.
View Existing Correlation
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Once the Dependent and Independent Data Types have been set, along with the start and end date, then if the "Refresh Chart" button is pressed after selecting one of the data types then a graph at the bottom of the window is visible which shows the data for the period. This is useful for checking that the data is available and complete for the whole period. In the screenshot above, HH consumption data from a Meter is being plotted against Occupancy data in an Associated Data item. |
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| Name | This is the name of the correlation that will be saved. If the "Use default name" checkbox is selected, the system will automatically generate one based on the names of the dependent and independent data types that have been selected for the Regressions. | |
| Selecting from Data of Type | When selecting the data to use in the Regression, both a Dependent Data Type and Independent Data Type must be selected. This drop down list allows you to select which streams of data you wish to use in the regression based on the data-sets which are available for the selected Site. | |
| Dependant Data Type | This is the stream data which might be influenced by the independent data type. It is usually metering data relating to electricity or gas consumed or potentially electricity generated. In terms of Sigma items, this could be a meter, periodic channel, non-periodic channel or virtual meter. This can be set by "dragging and dropping" the appropriate item from the "Available Data Type" in the list above. | |
| Independent Data Type | This is the data which might influence the dependent data type (for example, degree days, air temperature, solar irradiance, production output etc.). In terms of Sigma items, this will usually be Associated Data and will show all the items that are available for the Site. This can be set by "dragging and dropping" the appropriate item from the "Available Data Type" in the list above. | |
| Dates | This sets the start and end date that the regression should be set for and the Timezone that should be used. The regression that is initially created will be for data that falls between these dates. Note - the dates can be updated subsequently when working with the Regression. | |
| Interval Period | The granularity that should be used when creating the Regression - i.e. the number of unique data points that should be used. The options here are:
For example, if a year long period is selected and an interval of One Month is used, then 12 data points will be included in the regression. Conversely, if One Week was selected, then 52 points would be included. Note - this should be set according to the length of time the Regression is being created for. If looking at a longer period of time, then a higher interval period might be used. |
Discover Correlations (Automatic)
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Correlations will be between two data sets and those found automatically will display as follows, the first item is the dependent data type, the second is the independent data type.
Regression
Upon entering a Regression Correlation, then the Regression screen will be displayed in the context of the Chart Tab.
This is where the Dependent Data Type (y axis or vertical axis) is plotted against the Independent Data Type (X axis or horizontal axis) and we can start working with the relationship between the two datasets and determine what expected performance might be. There are a number of components in this screen, which are explained in the subsequent sections below.
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- Date (and time if applicable)
- X value - the value of the independent variable
- Y value - the value of the dependent variable
- Y deviation - the difference between the expected performance based on the regression line and the actual value (e.g the regression line expects the consumption to be 50 based on the production output being 10. The actual value is 75, so the Y deviations would be 25).
- A positive value indicates deviation above the regression line, a negative value indicates deviation below the regression line
- Included - a tickbox which shows whether or not the data point is included in the regression. These can be selected or deselected as required.
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Cumulative Sum (CuSUM)
Once the Regression Correlation has been created and the expected performance determined, then the CuSUM control chart can be used to view the performance of the dependent variable over time. More details about this can be seen on the introduction page here.
This can be accessed by clicking on either "CUSUM" links at the top of the screen:
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Chart Tab
The graph shows the cumulative data based on the CuSUM period.
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The Targets will only create an event if the first point of data is outside the tolerance range by >5% or if there are two consecutive points of day outside the tolerance range but with the 5% range.
Table Tab
Selecting the 
tab to show the data points that are plotted on the graph
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Navigate from Regression to the Control Chart via CuSUM by clicking 
then 
Graph
The graph will display data for the same period that has been set in the CuSUM
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