Is there a way to scan scan for null values? In other words, is there a way to evaluate in TC2000 whether an expression can be evaluated for a particular stock?  I realize I am asking "Is there a way to scan for something that is unscannable?"

For instance if I wanted a scan condition that included the weekly price from 200 weeks ago (c200[weekly]) the results would not include any companies less than 4 yeas old.  However, one might be interested in a watchlist of just those young companies.  I realize I could put c200-weekly into a column in a watchlist and just look for the companies that show a blank but I would like to scan for that condition, the condition that renders a blank in that column.  Something like (c200>0)=false or ABS((c200>0))=0

Apologies if this has already been asked and answered

Unfortunately no. You can sort for something like an IPO that has a blank value but not scan for it.