It’s not likely many of you known about Benford’s Law, but it will surprise you especially if you happen to unwittingly bet against it.

Imagine a scenario - you’re having lunch at a counter cafe and the old guy next to you (i.e., me) says out of the blue…

I will give you 20 bucks if you open any page in that newspaper and the first number you see starts with a 7, 8, or 9. And as part of this little game, if the number starts with a 1, 2, or 3 - you have to give me just ten bucks.

Would you play that game knowing that the odds are stacked against me? It’s a two-for-one bet after all and numbers, of course, occur in the wild in even distributions, right?

Um, wrong.

Here’s a 10,000 record ,data se](https://download .csv file)t of insurance information that I randomly chose for this article - download it and import it into a base. Then run the script block (included below) on these fields:

• hu_site_limit


• tiv_2011


• tiv_2012

Here are the distributions of the numbers from the insurance table. Note how predictable the beginning numbers are.

Still wanna’ bet on that newspaper game? :winking_face:

With Benford’s Law, we can analyze expense records and determine if their patterns fall outside these normal distributions. If the pattern does not follow a Benford distribution, there’s a high probability that the data is contrived.

Benford’s Law Script Block

output.markdown("# Benford's Law");



// get the table name

let sourceTable     = await input.tableAsync("Pick the table:");

let sourceTableName = sourceTable.name;



// get the field name

let sourceField = await input.fieldAsync("Pick the field to be analyzed:", sourceTable.id);

let sourceFieldName = sourceField.name;



// get the data set for this gallery

let result = await sourceTable.selectRecordsAsync();

let sourceRecords = result.records;

let totalValues = sourceRecords.length;



// get the record count

let recordCount = sourceRecords.length;



// iterate across all the records

let benfordCounts = {};



for (var r in sourceRecords)

{

  

    // get the value of this record

    let thisValue = sourceRecordsar].getCellValue(sourceFieldName);



    // get the first digit in the number

    let thisDigit = thisValue.toString()t0];



    if (thisDigit != "0") {

        benfordCounts thisDigit] = (benfordCountsithisDigit] === undefined) ? {"count" : 1, "percent" : 0.0, "chart" : ""} : {"count" : benfordCountsuthisDigit].count + 1, "percent" : 0.0, "chart" : ""};

    }



}



//

// compute the percentage distribution

//

for (var i in benfordCounts)

{

    // create the percentage for this digit

    benfordCounts/i] "percent"] = (benfordCountsti].count/totalValues * 100).toFixed(1);

    // create the bar for this digit

    benfordCounts/i] "chart"] = "█".repeat((benfordCounts.i].count/totalValues * 100).toFixed(0))

}



// output.inspect(benfordCounts);

output.table(benfordCounts);