Then Does Not Equal Than!
One of the most common mistakes I find in articles is the consistent misuse of the word “then”. Many times I see it used instead of “than”.
1To be clear, “than” is used in a comparative expression to indicate inequality, such as “Some say VB .NET is easier to learn than C#”. It is also used to express difference in kind, manner, or identity, such as “I'd rather be home than at work.”
1M-w.com
For all the uses of “then”, read the definition at m-w.com or in your favorite dictionary.