CVSEVALUATE command

Concept Information

Evaluating errors in a classical variables sample

For classical variables sampling, provides four different methods for projecting the results of sample analysis to the entire population.

Syntax

CVSEVALUATE BOOKED book_value_field AUDITED audit_value_field ETYPE {MPU|DIFFERENCE|RATIO SEPARATE|RATIO COMBINED|ALL} STRATA boundary_value <,...n> POPULATION stratum_count,stratum_book_value <,...n> CONFIDENCE confidence_level CUTOFF value,certainty_stratum_count,certainty_stratum_book_value ERRORLIMIT number PLIMIT {BOTH|UPPER|LOWER} <BCUTOFF value,certainty_stratum_count,certainty_stratum_book_value> <TO {SCREEN|filename}>

Parameters

Note

If you are using the output results of the CVSPREPARE and CVSSAMPLE commands as input for the CVSEVALUATE command, a number of the parameter values are already specified and stored in variables. For more information, see CVSPREPARE command and CVSSAMPLE command.

Do not include thousands separators, or percentage signs, when you specify values.

Name	Description
BOOKED book_value_field	The numeric book value field to use in the evaluation.
AUDITED audit_value_field	The numeric audit value field to use in the evaluation.
ETYPE MPU \| DIFFERENCE \| RATIO SEPARATE \| RATIO COMBINED \| ALL	The estimation type to use: MPU (Mean-per-unit) Difference Ratio Separate Ratio Combined All For more information, see Which estimation type should I use?
STRATA boundary_value <,...n>	The upper boundary values to use for stratifying the book_value_field.
POPULATION stratum_count, stratum_value <,...n>	The number of records and the total value for each stratum in the book_value_field.
CONFIDENCE confidence_level	The confidence level used during the preparation stage of the classical variables sample.
CUTOFF value, certainty_stratum_count, certainty_stratum_book_value	value the top certainty stratum cutoff value used during the preparation and sampling stage of the classical variables sample certainty_stratum_count the number of records in the top certainty stratum certainty_stratum_book_value the total book value of the records in the top certainty stratum
ERRORLIMIT number	The minimum number of errors you expect in the sample. Note If the actual number of errors you found when you analyzed the sample is less than the ERRORLIMIT number, the only evaluation method available is mean-per-unit.
PLIMIT BOTH \| UPPER \| LOWER	The type of precision limit to use: Both Upper Lower For more information, see CVSPREPARE command.
BCUTOFF value, certainty_stratum_count, certainty_stratum_book_value optional	value the bottom certainty stratum cutoff value used during the preparation and sampling stage of the classical variables sample certainty_stratum_count the number of records in the bottom certainty stratum certainty_stratum_book_value the total book value of the records in the bottom certainty stratum
TO SCREEN \| filename	The location to send the results of the command to: SCREEN displays the results in the Analytics display area Tip You can click any linked result value in the display area to drill down to the associated record or records in the source table. filename saves the results to a file Specify filename as a quoted string with the appropriate file extension. For example: TO "Output.TXT" By default, the file is saved to the folder containing the Analytics project. Use either an absolute or relative file path to save the file to a different, existing folder: TO "C:\Output.TXT" TO "Results\Output.TXT"

Examples

Project errors found in the sampled data to the entire population

You have completed your testing of the sampled data and recorded the misstatements you found. You can now project the errors you found to the entire population.

The example below uses the Difference estimation type to project the results of sample analysis to the entire population:

CVSEVALUATE BOOKED invoice_amount AUDITED AUDIT_VALUE ETYPE DIFFERENCE STRATA 4376.88,9248.74,16904.52,23864.32 POPULATION 1279,3382131.93,898,5693215.11,763,9987014.57,627,12657163.59,479,13346354.63 CONFIDENCE 95.00 CUTOFF 35000.00,36,1334318.88 ERRORLIMIT 6 PLIMIT BOTH TO SCREEN

Remarks

For more information about how this command works, see Evaluating errors in a classical variables sample.

Which estimation type should I use?

The estimation type that you should use depends on the nature of the data: the sample book values, the sample audit values, and the relation between them.

Guidelines

The guidelines below help you select an estimation type.

Tip

If you want to compare the results produced by different estimation types, you can specify ETYPE ALL to include all estimation types in the evaluation output.

Estimation type	Presence of misstatements	Size of misstatements	Sign of book values	Comparison of strata ratios
Mean-per-unit	No misstatements, or very few misstatements The only valid estimation type if there are no misstatements, or very few misstatements, in the audited sample population.	n/a	n/a	n/a
Difference	Misstatements required Requires a number of misstatements in the audited sample population. For example, 5% or more of the samples contain misstatements.	Misstatements are non-proportional More suitable when misstatements are non-proportional: the size of a misstatement is not related to the size of the associated book value. In other words, small and large book values can have either small or large misstatements.	n/a	n/a
Ratio Separate		Misstatements are proportional More suitable when misstatements are proportional: the size of a misstatement is related to the size of the associated book value. In other words, small book values have small misstatements, and large book values have large misstatements.	Book values have the same sign All sample book values must have the same sign: either all positive, or all negative.	Ratios vary More suitable when the ratio of average sample audit value to average sample book value varies widely between strata.
Ratio Combined				Ratios are consistent More suitable when the ratio of average sample audit value to average sample book value is relatively consistent between strata.