Which algorithm is used for dividend adjustment of Yahoo data?
Author: bliss
Creation Date: 11/28/2017 7:50 PM
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bliss

#1
Thanks to Eugene for helping me update my extensions to current Y! data.
Used Y! data adjusted for dividends, but didn't get expected result.
Wondering what algorithm is used for this task and why it differs from other dividend adjusted data such as presented at 'StockCharts.com' ?
Looking to get source data correlated to known baseline before proceeding to use tool for historical analysis.
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Eugene

#2
While I may have little idea about the expected result, the formula is documented in the User Guide: Data > Data Manager > Create New DataSet > Data Providers > Yahoo!.

Please please search the forum before posting, our search is nearly instant:

How is Yahoo data adjusted for dividends?

We believe our algorithm is the best. For more insight you might want to read Cone's posts (which is a good idea per se) #8 and #10 here:

Yahoo Data: MRO and NOC split adjustments not applied
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bliss

#3
Ok Eugene, thanks.
Agree, your dividend adjust algorithm looks fine. So problem with Y! data must be elsewhere.
See now from the thread, your manual workarounds for spits suggests that may be part of the problem.
Guess bottom line was stated by Cone...."Wealth-Lab is not a data provider".
Presumably each user needs to establish their preferred data source and WL will provide adapters as needed.
Is that correct?
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Eugene

#4
Sorry if I wasn't clear when saying "While I may have little idea about the expected result..." but this meant to tell that I have no clue about the problem you might be having with Yahoo data.

Detailed description appreciated. As this page suggests, "Show me":

How to Report Bugs Effectively
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bliss

#5
Thanks for the opportunity Eugene.

Personally, don't see this as a bug fix, rather more like a requirements change.
Thought it was common knowledge Y! data is flawed. You guys discussed it here and heard it from at least one other reliable source. Not sure its all that constructive to patchwork that data on case by case basis.

For me, a tab in data manager to create data sets using 'stockcharts' data with options for adjusted or unadjusted would solve my problem. Pretty sure this is a more widely respected data source, although understand there's a membership cost involved to use it.

But again, gets back to basic requirements for WL. Are you providing quality data sources for technical analysis, or just free sources with adapters as needed to accommodate user generated data?

Basic Requirement description something like: Provide quality historical price data adjusted for external perturbations (such as distributions, dividends, splits or whatever) to ensure price movement based on pure technical market forces.

This may be outside your basic mission here, so fully understand if that's the case.
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Eugene

#6
William, many things Yahoo were discussed in the last 1 1/2 decades. But things change. For example, after this Spring/Summer's revamp we noticed improvements to Y's split data quality.

But I see I still fail to make it clear. You're talking about a Y! data problem evident to you only, skipping the entire troubleshooting part to make high-effort suggestions like building a new data provider. Thing just don't work this way. Could you give us an example that illustrates what you think is wrong with the Y! provider's dividend adjustment, please?

QUOTE:
Basic Requirement description something like: Provide quality historical price data adjusted for external perturbations (such as distributions, dividends, splits or whatever) to ensure price movement based on pure technical market forces.

You're describing Wealth-Data:

https://www.wealth-data.com/
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bliss

#7
Thanks for reminder Eugene, forgot that Wealth-data was next on my list.
Got the link from your welcome email and was meaning to try it out before getting distracted with Y! data.

But a couple of questions about how to get it started
1. Need help finding or installing WLD adapter. Don't have a tab in Data Manager. ASCII, Fidelity, and Y! are only tabs available. Searched help file. Noticed create new data set gives option for WL4 files, but not for WLD4 Format Data files as shown in help.
2. Signed up for WLD, but have no clue how to access the source for existing WL users. The free link points to "get wealth labs", so reluctant to follow that link. Wondering how the site will identify me as an existing WL user.

Sorry for all the mundane requests, but these setups aren't really all that clear.

Will get back to you on Y! after exhausting other options.
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Eugene

#8
We try to keep the forum searchable and organized. The topic says "Which algorithm is used for dividend adjustment of Yahoo data?" so let's be exhausting other (Wealth-Data related) options in a new topic, please. tia.