Sharescope / Mytrack discrepancies

[olwenh]

I've just been checking some data & have a huge discrepancy between sharescope & mytrack.

15th April DOW,

Sharescope H=8443, L=8251
Mytrack H=8402, L=8307

Can anyone throw some light on it?

I know a few people have warned about the quality of the mytrack eod data - but this is from the intraday & as far as I can see the dow traded within the mytrack range on that day.

Sharescope data is eod, mytrack is intraday.

 

[mmillar]

Someone else recently posted the explanation of this with regards to Yahoo data, so they can take the credit for this explanation.

It appears there are two ways of calculating the high of the day for an index...

1. During the day the Dow index varies minute by minute according to where the prices of its 30 constituent stocks are at that point in time. When the average of these 30 stocks is at its highest point then we get the high of the day. This is the high that Mytrack has given you (8402). Yahoo gives this data as ^DJI1

2. After the close you just take highs for each of the 30 constituent stocks, no matter what time they occured, and calculate your index. This method will always give you a higher value then 1 (because it assumes all 30 highs occured at the same time, which is not true). This is the high that Sharescope has given you (8443). Yahoo gives this data as ^DJI

I think that most people would regard 1 as the true high and 2 as a bit bizarre, but I'm not prepared to get into an argument about it - each to his/her own and all that.

cheers

 

[olwenh]

thanks, that's brilliant,

I thought I was getting something really obvious wrong - like looking at the wrong dates.

That's a huge difference in values. I've been using the 10day avg range & some values were taken from ss & others from sierra.

 

[FTSE Beater]

Hi all

I believe it is to do with the time you download the data - or it used to be.

Sharescope takes its data at about 4:30 our time, so the Dow will have only just started and hence the difference in data.

HTH, but if in doubt, go with Mytrack.