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I think data (as in raw, collected / measured / surveyed data) doesn't really change, but you get more of it. Some data may occasionally supersede old data. May
by quickthrower2 7y ago
I think data (as in raw, collected / measured / surveyed data) doesn't really change, but you get more of it. Some data may occasionally supersede old data. Maybe the schema of the data changes, so your first set of data is in one form, and subsequent data might have more information, or recorded in a different way.
- jon_richards 7y agoOne really important feature of time series data is the preservation of what the dataset looked like at each point in time. Financial data providers will make a mistake (off by order of magnitude, missed a stock split, etc) and then go back and correct it. This means you end up training models entirely on corrected data, but trade based on uncorrected data.
- cbenz 7y agoThat's exactly the reason why we created https://db.nomics.world https://db.nomics.world
- quickthrower2 7y agoThanks, I didn't consider training of models, this is a great use case for a tool.
- timsehn 7y agoWe think this is the assumption (that data does not change) but we don't think it holds and data diffs help show you when something you did not expect did change.