Reliability of price data

Data is very important to a chartist. If bad data was used, garbage in garbage out. In order to determine how effective the data source is, a chartist has to determine the following:

1. Reliable data

a. Get data that is supplied by a credible source, such as a reputable  vendor or even directly from the stock exchange
b. Take steps to check the data against other sources for consistency

2. Data adjustments

a. Check whether back data is adjusted for corporate events such as special dividends, placements or stock splits
b. Ask how quickly data adjustments are provided
c. If unsure, write to the data vendor for advice
d. Paid data usually surpass in quality and usefulness compared to free data; data vendors know the importance of customer’s concerns – for a fee.

Sources of reliable data:

  • Yahoo! Finance (free; up to 50 exchanges but data for Singapore not adjusted)
  • Analyst’s DataServer (One-time fee for Singapore EOD adjusted data and global indices)