Using weights (r9)

In ideal circumstances, survey data reflects the population it is meant to represent. When this is not the case, responses can be weighted to align the data with the population. For example, if your survey data consists of 60% men and 40% women, you could weight the responses from men by 0.83 and the responses from women by 1.25 to approximate a 50/50 split.

The Weights applet allows users to create and upload weights. The weight values are calculated automatically based on the survey data and the targets that you specify. Weights can then be applied in Crosstab reports and TURF Analysis.

To access the Weights applet, select the Weights option in the Analytics applet group. All survey roles except for Limited users can access the Weights applet.

Like the rest of the Analytics applets, the Weights applet will not be available until the survey has been published for the first time. The Weights applet always uses the latest published version of the survey.

Overview

The Weights applet provides a list of all weights that have been built or uploaded for the survey. Click the View button to switch to a compact view of the list.

The following information is provided for each weight. 

Column	Description
Weight ID	The unique ID given to the weight when created.
Weight Desc	A brief description of the weight. By default, the system will use the question or variable's text for this field.
Weighted Fields	The field(s) the weight has been applied to.
Filter/Data Cut	The data cut selected for use when creating the weight.
Min	The minimum trimmed weight value; 0.3 is commonly used for the minimum. If a minimum wasn't specified, this displays the lowest calculated weight value across all of the options to achieve the specified Target %.
Max	The maximum trimmed weight value; 3.0 is commonly used for the maximum. If a maximum wasn't specified, this displays the highest calculated weight value across all of the options to achieve the specified Target %.
Rescaled	Indicates with a checkmark if the weights have been scaled to keep the total N consistent with the unweighted data.
Uploaded	Indicates with a checkmark if the weight values were uploaded instead of system-generated.

Creating weights

Weights are created using the Build New or Upload New buttons. Click the Build New button to create weights based by entering target percentages for one or more survey fields. The software will calculate the weight values for you. Click the Upload New button to upload weight values using an Excel file.

Building weights within the applet

To create a new weight, click the Build New button above the list of weights. On the screen that appears, select one or more survey fields from the Weighting Fields dropdown menu, using the reporting field tree. Then, select which records to include. The Completed option is selected by default – uncheck it to use all records instead. You can also filter based on IDs, Date/Time, or Data Cuts. See Report Builder for information on filtering records. 

When you're satisfied with the fields and record settings, click the Next button.

The next screen displays a list of every option for the fields selected on the previous screen. The Original % column provides the current percentages based on the record filter settings from the previous screen. Click on the percentages in the Target % column to change them to the desired values. The weights needed to reach these targets will be calculated automatically. The total for the Target % column must add to 100% for each field.

Trimming weights

The larger the difference between the highest and lowest weight values, the more the survey data's overall accuracy will be affected by the weights. To mitigate this, weights can be "trimmed" to set a limit on the range of allowed weight values. Use the Minimum and Maximum fields to set these limits. Check the Scale weights to maintain total N box to keep the total N of the weighted data consistent with the unweighted data.

You may also update the Weights Description field as needed. When you're ready, click the Finish button to build the weight.

On the next screen, review the final weight values. Click Confirm to save the weight.

Uploading new weights

To upload new weights, click the Upload New button above the list of weights. Enter a description in the Weight Description text field, and click Select Weight File to choose a file from your computer. The file will be uploaded and processed automatically. If there is an issue with the file, an error message will be displayed.

Click Confirm to save the uploaded weight.

Upload format

The weights file must have only two columns – an 'id' column, and a weight column. The 'id' column must contain the record IDs of respondents in the data set. The weight column must be labeled with a Weight ID. This ID cannot contain spaces and must be unique to any pre-existing weights in the survey. The data in the weight column should contain the corresponding weight values for each respondent ID in the adjacent column.

Viewing results

To view a weight's results, double-click on it in the list, or single-click directly on the Weight ID. You can also click the Results button when a weight is selected. Results are only available for weights created using the Build New button.

This screen provides the following information in two sections, Variables and Key Weighting Stats. 

The Variables section lists all fields and options used in the weight calculation, with the following values:

• Original % – The percentages for the unweighted survey data.
• Target % – The targets entered by the user who created the weight.
• Weighted % – The final weighted percentage achieved by the system's algorithm.

The Key Weighting Stats section provides the Min and Max weights applied, with the following types included:

• Untrimmed – The lowest and highest calculated weight value across all of the options to achieve the specified Target %.
• Trimmed – The Min and Max weight values specified when the weight was created. 
• Rescaled – The Min and Max calculated if the Scale weights to maintain total N option was checked when the weight was created.

Applying weights in a report

Weights may be utilized in Crosstab reports and TURF analyses.

Crosstab reports

To apply weights in a Crosstab, use the dropdown menu in the Crosstab Editor, under Display Options and Filters.

When weights are applied to a Crosstab report, both the weighted and unweighted base sizes will be displayed.

TURF Analysis

To apply weights to a TURF Analysis, select the Weights checkbox next to the record filters, then choose the desired weights from the dropdown menu. 

Downloading weights

To download weights, click on a weight to select it, then click Download from the  Actions menu. 

Downloaded weights include the status of each record. If the weight was created in the Weights applet, the field used to calculate the weight is also included.

Uploading to existing weights

Weight values may be overwritten by uploading a file directly to pre-existing weights. Click on a weight to select it, then click Upload from the  Actions menu. 

Click the Select Weight File button, and choose a file from your system. Once the file is finished uploading, click Confirm to save the new weight values.

Upload format

The weights file must have only two columns – an 'id' column, and a weight column. The 'id' column must contain the record IDs of respondents in the data set. The weight column header must match the Weight ID of the weight selected. The data in the weight column should contain the corresponding weight values for each respondent ID in the adjacent column.

Recalculate weights

The Recalc option allows users to update the selected weight's values. Use this tool to recalculate weights after additional data has been collected.

Edit weights

To edit an existing weight, click on it, then select Edit from the Actions menu. This will take you through the steps detailed in the Building weights within the applet section above, where you can modify any of the weight's settings.

Delete weights

To remove a saved weight from the survey, select Delete from the Actions menu. A confirmation pop-up will appear to confirm the weight's deletion.