Dow Theory

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Charles Dow one hundred years ago fashioned the idea that the stock market would continue to move higher if two sectors of the market moved commensurately. The two sectors are the Industrials and Transportation. This simple observation has captured the minds of many on wall street and is nutured by none other than the "Wall Street Journal". (Did you ever wonder why on the inside they have charts of the DowJones Industrials, Dow Jones Transportation, Dow Jones Utilites?) Needless to say, many investors follow this simple roadmap, and in concert, act to move the market. So as a smaller investor you need to periodicly review Charles Dow's relationship. Below are the only charts you need to follow his advise. Please note that the charts below are all daily high-low-close charts.

For more details regarding Dow Theory, visit the following links:

Dow Theory by Stockcharts.com
Dow Theory by incrediblecharts.com

For more information regarding the Dow Jones Indices and hostorical changes to the Dow visit:

Dow Jones & Company

For a little technical analaysis history lesson:

Dow Theory History by DowTheoryLetters.com
Dow Theory History by Fools.com

Quotations

Price Data:

Be aware that the Dow Jones Industrial Average daily prices can be found in two forms -the actual price and the theoretical price. This means that all quotes are not interchangeable. However, prior to January 1992 the Dow Jones Industrial Average was primarily quoted in the theoretical format. Rarely were actual prices published as the DJIA was not updated throughout the day in real-time. If actual prices were quoted, they were computed by a data supplier and proprietory to that data supplier.

Volume Data:

A word about DJIA quotations found on the web. For those of you attempting to create your own Dow charts from data on the web, here's a short review of the following web source's data:

Yahoo's historical data - INACCURATE! The daily volume posted resembles the NYSE trading volume if mulitplied by a factor of 1000. In addition, the monthly volume doesn't match the daily volumes posted.
MSN.com historical data - INACCURATE! Their daily quotations are the same as Yahoo's daily quotations except that MSN's quotes show the volume to be in the billion share range. Also annoying is that some days are off by a factor of 1000 so you have to correct some of the daily data. Regardless, these daily quotes are wrong. On the plus side, the monthly data is consistent with the daily data posted. And while this is better than Yahoo's monthly data, it still is the wrong data. The daily data doesn't represent the daily trading volume of the DJIA. At this time, the most likely guess is that it is the NYSE's trading volume.
Bigcharts.com historical data - OK within 3%. This is the most accurate source for FREE historical daily quotes, but the daily volumes are somewhat error prone. However, these errors are typcially within 3% of the actual volumes. At this time, it is known if they represent corrected or adjusted data, or if some days are off by 3%.
Prophet.net charts of the DJ30 - INACCURATE! Their interactive chart of the DJ30 shows the NYSE daily volume rather than the DJIA's trading volume.
Bloomberg.com - ACCURATE! This is a reliable source for the DJIA's trading volume. However, they to not post historical data. Only the current day's data is available. They post regular trading hours volume.
Quote.com - ACCURATE! This is a reliable source for the DJIA's trading volume. However, they to not post historical data. Only the current day's data is available. They post regular trading hours volume.
MarketVolume.com - OK, but different data is used. This site posts an aggregate total trading volume from all exchanges including pre-market and after-market hours. So this figure is typically higher.
CNNmoney money.cnn.com - Delayed but accurate. They post regular trading hours volume 1 to 2 minutes after eSignal.com.

Summary: Bloomberg.com, and Quote.com are accurate sources. Marketvolume.com is also accurate but includes volume from everywhere and from pre and post market hours. CNNmoney is also an alternate site for reliable free DJIA quotes.