How Good Is Your Data? by Sunny Harris
ARTICLE SYNOPSIS ...Is all data equal? If truth be told, I never gave it much
thought. I have been using one vendor nearly exclusively
for about 20 years. My fills are good enough. My closing
prices seem to match what I see on television or find
online. As long as the profits roll in, there has been no
reason to question the data.
But then I was told by another vendor that my vendor's
data is off by just enough to generate a side income,
through the slippage from actual price to the price I
am presented. My curiosity was piqued, and so I decided to
investigate. First, I set up a spreadsheet an...