问题
Suppose I want to regress in R Gross Profit on Total Revenue. I need data for this, and the more, the better. There is a library on CRAN that I find very useful: quantmod , that does what I need.
library(quantmod)
getFinancials(Symbol="AMD", src="google")
#to get the names of the matrix: rownames(AMD.f$IS$A)
Total.Revenue<-AMD.f$IS$A["Revenue",]
Gross.Profit<-AMD.f$IS$A["Gross Profit",]
#finally:
reg1<-lm(Gross.Profit~Total.Revenue)
The biggest issue that I have is that this library gets me data only for 4 years (4 observations, and who runs a regression with only 4 observations???). Is there any other way (maybe other libraries) that would get data for MORE than 4 years?
回答1:
I agree that this is not an R programming question, but I'm going to make a few comments anyway before this question is (likely) closed.
It boils down to this: getting reliable fundamental data across sectors and markets is difficult enough even if you have money to spend. If you are looking at the US then there are a number of options, but all the major (read 'relatively reliable') providers require thousands of dollars per month - FactSet, Bloomberg, Datastream and so on. For what it's worth, for working with fundamental data I prefer and use FactSet.
Generally speaking, because the Excel tools offered by each provider are more mature, I have found it easier to populate spreadsheets with the data and then read the data into R. Then again, I typically deal with the fundamentals of a few dozen companies at most, because once you move out of the domain of your "known" companies the time it takes to check anomalies increases exponentially.
There are numerous potential "gotchas". The most obvious is that definitions vary from sector to sector. "Sales" for an industrial company is very different from "sales" for a bank, for example. Another problem is changes in definitions. Pretty much every year some accounting regulation or other changes and breaks your data series. Last year minorities were reported here, but this year this item is moved to another position in the P&L and so on.
Another problem is companies themselves changing. How does one deal with mergers, acquisitions and spin-offs, for example? This sort of thing can make measuring organic sales growth next to impossible. Yet another point to bear in mind is that if you're dealing with operating or net profit, you have to consider exceptionals and whether to adjust for them.
Dealing with companies outside the US adds a whole bunch of further problems. Of course, the major data providers try to standardise globally (FactSet Fundamentals for example). This just adds another layer of abstraction and typically it is hard to check to see how the data has been manipulated.
In short, getting the data is onerous and I know of no reliable free sources. Unless you're dealing with the simplest items for a very homogenous group of companies, this is a can of worms even if you do have the data.
来源：https://stackoverflow.com/questions/10177435/get-annual-financial-data-for-a-stock-for-many-years-in-r