ayla, two Q's regarding your chart VIX2006.xls:
1. Is there a reason why the column F (Volume) values are inconsistantly entered?
2. Is there a reason why the "Date' data fields in columns A & M do not match up beginning on row 201 and ending on row 724?
I really want to learn and understand.
Thanks.
I have rechecked the data and it still looks good to me though I totally understand why you are asking the questions. I should have explained this initially.
1. - Column F is an exact replica of what I downloaded from Yahoo for ^VIX. I can't answer why they are inconsistent. I remember having the same question myself. But I left it in because if you want to update the data, it is a simple cut and past from:
http://finance.yahoo.com/q/hp?s=^VIX
2. Reasons columns A & M don't line up:
Columns A thru L is actually a different database (i.e. Yahoo) than columns M, R, S, T, and U. Getting these matched up using the common variable of "date" is the reason Column M and Column A aren't lined up. Since Number of dates in TSP datebase is less than number of dates in YAHOO VIX database.
It might have been clearer for you to see this if I would have just provided two data sheets instead of putting the data side by side. I may do that in future uploads.
Note column Q is labeled "VIX - date Matched", not just 'VIX" because it has been extracted from column G only when the date in column M for the same row is found in Column A.
More details:
Col A in VIX data downloaded from YAHOO includes extra dates not included in the TSP date column M. This mismatch causes some extra effort to be made (which I should have explained). Data posted in columns N,O,P and Q are extracted from columns G, I J and K after successful match in the YAHOO date column. The value is extracted (using an Excel "index" formula) and posted.
For example, the first date in Column M (M201) which is Nov 5, 2004 has a value for the VIX that is extracted from the value in Column E (E 205). Can't just pull out the VIX value from the same row since VIX dates don't necessarily line up with TSP dates not just because of my sloppiness but the databases of dates are not the same.
I could have been less sloppy and at least started the dates out correctly side by side but Column M will always eventually "fall behind" column A in this example because there are holidays that cause dates to be excluded from the TSP date database that ARE included in the YAHOO VIX date database.
Bottom line is that the chart is ONLY made using entries from Column M thru U. As long as this data and the corresponding date is correct, that is the most important.
BUT.. the reason the other data is there is that the data in Columns A thru N is the raw data from Yahoo that is needed to eventually end up in Columns N thru Q.
Columns M, R, S, T and U are extracted from the TSP share price chart (and sorted in ascending mode) from:
http://www.tsp.gov/rates/share-prices.html
I did some spot checking in case I made some errors (like I have definitely made before) and it looks good. I picked a date from column N, and looked at it from the TSP share database and compared it to the IFUND in column U and they matched. I also made sure the VIX number in column Q for a TSP date (in column M) matches a VIX number in column G for the identical VIX date (in column A).
Probably clear as mud. Sorry, I've answered this by repeating a lot. I may try to create two data sheets as explained above but in the meantime, only look at columns M thru U. That is what the chart uses. But if you ever want to update the chart, you MUST update columns A thru N.
Feel free to check columns M, R, S, T, & U and let me know if any rows have errors as compared with the TSP share database.
Also, let me know if you see erros from columns A thru N as compared with the YAHOO VIX database. But please don't worry if columns M,R,S,T, & U do not line up row by row with columns A thru N. (Notice the length of the TSP date is shorter than the length of the VIX date column A - and will almost always be shorter if date interval covers any government holidays.)