Identifying Unusual Patterns that Might Indicate Data Integrity Issues

See how to:

• Explore Patterns
• Identify duplicate values
  • Find Most Duplicated Values - values that appear most frequently within column                                         
  • Find Longest Runs - values that repeats in consecutive rows within column
  • Find Longest Duplicated Sequences- sequence of values that repeats within column
  • Find Duplicates Across Columns- sequence of values that appears in the same rows across multiple columns
  • Use Rarity Score to interpret duplications
    • Conceptually a pattern is about as likely as getting [rarity value] heads in a row when flipping a fair coin
    • Statistically, -Log2(p);  where p is probability of pattern assuming random ordering of values                                                            
• Identify unusual values                                                          
  • Locate Formatted Width within cells - both overall and decimals
  • Locate suspicious Fraction Lengths        
  • Locate suspicious Leading Digits that are too uniform
    • Check distribution of leading digits against Benford's Law, which says, that in many naturally occurring groups of numbers, distribution of leading digit is not uniform

    • Log10( (d+1) / d), where d is leading digit 

• Identify unexpected linear relationships where, within some group of consecutive rows (default is 10), one column has an exact linear relationship with another column
• Identify specification limit anomalies for columns with spec limit properties
  • Locate Spec Limit Matches where limits in cells exactly match LSL or USL
  • Compare Spec Limits Distribution to compare out-of-spec values to expected out-of-spec values

Resources:

• Kurt Schwitter  on continued fraction