Performing Benford analysis

Benford analysis predicts the number of times each leading digit or digit combination will occur in a data set, and compares the expected count to the actual count.

To perform Benford analysis:

  1. Select Analyze > Perform Benford Analysis.
  2. On the Main tab, do one of the following:
    • Select the field to analyze from the Benford On drop-down list.

    • Click Benford On to select the field, or to create an expression.

  3. Enter the Number of Leading Digits, between 1 and 6, that you want to analyze.
    Note

    If you are analyzing four or more leading digits, results output must be sent to a file. Results of analyzing four or more digits cannot be displayed on the screen, sent to the printer, or displayed in a graph.

  4. If there are records in the current view that you want to exclude from processing, enter a condition in the If text box, or click If to create an IF statement using the Expression Builder.

    The IF statement considers all records in the view and filters out those that do not meet the specified condition.

  5. If you want to display counts that are significantly outside expectations, select Include Upper and Lower Bounds.

    Bounds are calculated based on the number of records in the data set and the number of digit combinations that are being analyzed. When more than one actual count falls outside the bounds, this suggests a non-random variation and should be investigated.

  6. Click the Output tab.
  7. Select the appropriate output option in the To panel:
    • Screen – Select this option to display the results in the ACL display area. If the output table contains a large number of records, it is faster and more useful to save the results to a file than to display the results on the screen.

    • Print – Select this option to send the results to the default printer.

    • Graph – Select this option to create a graph of the results and display it in the ACL display area.

    • File – Select this option to save or append the results to an ACL table. The table is added to the open project if it is not already in the project.

    Note

    Output options that do not apply to a particular analytical operation are disabled.

  8. If you selected File as the output type, specify the following information in the As panel:
    • File TypeACL Table is the only option. Saves the results to a new ACL table, or appends the results to an existing ACL table.

    • Name – Enter a table name in the Name text box. Or click Name and enter the table name, or select an existing table in the Save or Save File As dialog box to overwrite or append to the table. If ACL prefills a table name, you can accept the prefilled name, or change it.

      You can also specify an absolute or relative file path, or navigate to a different folder, to save or append the table in a location other than the project location. For example: C:\Results\Output.fil or Results\Output.fil.

    • Local – Only enabled when connected to a server table. Select Local to save the output table to the same location as the project, or to specify a path or navigate to a different local folder. Leave Local deselected to save the output table to the Prefix folder on the ACL Server.

      Note

      For output results produced from analysis or processing of ACL Analytics Exchange server tables, select Local. You cannot use the Local setting to import results tables to ACL Analytics Exchange Server.

  9. Depending on the output type, you can optionally specify a Header and/or a Footer in the text box(es).

    Headers and footers are centered by default. Type a left angle bracket (<) before the header or footer text to left align the text. Click Header or Footer to enter a header or footer of more than one line. Alternatively, you can enter a semi-colon (;) as a line-break character in the header or footer text box. Left aligning multiple lines requires a left angle bracket at the beginning of each line.

  10. Click the More tab.
  11. Select the appropriate option in the Scope panel.
    • All – This option is selected by default. Leave it selected to specify that all records in the view will be processed.

    • First – Select this option and enter a number in the text box to start processing at the first record in the view and include only the specified number of records.

    • Next – Select this option and enter a number in the text box to start processing at the currently selected record in the view and include only the specified number of records. The actual record number in the leftmost column must be selected, not data in the row.

    • While – Select this option to use a WHILE statement to limit the processing of records in the view based on a particular criterion or set of criteria. You can enter a condition in the While text box, or click While to create a WHILE statement using the Expression Builder.

      A WHILE statement allows records in the view to be processed only while the specified condition evaluates to true. As soon as the condition evaluates to false, the processing terminates, and no further records are considered. You can use the While option in conjunction with the All, First, or Next options.

    Note

    The number of records specified in the First or Next options references either the physical or the indexed order of records in a table, and disregards any filtering or quick sorting applied to the view. However, results of analytical operations respect any filtering.

    If a view is quick sorted, Next behaves like First.

  12. If you selected File (ACL Table) as the output type, select or deselect Use Output Table depending on whether or not you want the ACL table containing the output results to open automatically upon completion of the operation.
  13. If you selected File as the output type, and want to append the output results to the end of an existing ACL table, do one of the following:
    • Select Append To Existing File if you are certain the output results and the existing table are identical in structure.

    • Leave Append To Existing File deselected if you want ACL to compare the record lengths of the output results and the existing table. If the record lengths are not identical, the data structure is not identical.

    Note

    Leaving Append To Existing File deselected is recommended if you are uncertain about the data structure. For more information about appending and data structure, see Appending results to ACL tables and text files.

  14. Click OK.
  15. If the overwrite prompt appears, select the appropriate option.

    If you are expecting the Append option to appear and it does not, click No to cancel the operation and see Appending results to ACL tables and text files.

Related concepts
Saving results and specifying results output folders
About Benford analysis


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