Compare the following:
http://usafacts.org/metrics/31815 vs http://usafacts.org/metrics/12966
In the second chart half a million more people decide to die every 10th year?
( imgur link to screenshots in case the links don't work: http://imgur.com/a/tY02j )
Or it's from another source that gives different metrics obtained every 10 years (e.g. from census) with some extrapolation?
In any case, the differences are small in this instance over the long run, it's the lack of source and other metadata that its more troubling.
In any case, the differences are small in this instance over the long run
The differences in those years are _huge_.
Except if the trend line is based on the other data source, and the peaks on the census data.
They look similar to me. One has less granular data than the other. What exactly are you implying?
Do a quick calculation for me, please.
What percent of 2 million is 500 thousand? Because the errors are 500 thousand on 2-2.5 million. That's a huge amount of error.
This still shows the flaws in the website. It does not say what the scale is in on graph at all, and other graphs will not be so obviously incorrect.
The big jumps on census years indicate that the census department does not estimate accurately when working with 9-year-old data.
They aren't jumps suddenly correcting a bad estimate with new data. They are gigantic 25% spikes which are then immediately undone. There is no way to explain this chart by just saying that estimates worsen over time.
I can't look at your link at the moment because the corporate firewall is currently blocking the domain.
But there really isn't any way to get around the fact that real census data are only collected once every 10 years (and the 1890 census was burned, so that point is missing).
To give a description of the problem in text...
Both charts are labeled "Deaths", but I'm going to describe one of them for you.
The time span from 1981 to 1999 goes like this:
1,968,365 - 1,998,559 - 2,033,124 - 2,068,679 - 2,091,359 - 2,105,024 - 2,163,984 - 2,161,764 - [1,637,394] - [2,656,721] - 2,180,115 - 2,226,027 - 2,282,854 - 2,284,363 - 2,317,918 - 2,321,933 - 2,330,759 - 2,359,088 - 2,386,995
And then 2000 is [2,979,442]
And then 2001 is 2,430,225
And so on. Every 10 years, and also in 1989, there is a fluctuation by 500,000 deaths from the expected number given the surrounding trends.
All of the numbers that are _not_ between  above look like a smooth upward trend, yeah?
So WTF is happening in the three that have  if the data isn't bogus? I say the data must be bogus.
 So I went and put "why is death rate higher in census years?" into the google search bar, and the first result is "Causes of Death - Census". I didn't actually click on the link to find out, but that title certainly sounds like the census kills people. So maybe you're right. :)
The estimates are just bad and not adjusted historically. Doesn't make the chart bad... just makes the data a little wonky.
There was (probably still is, despite the fact that it seems to be a lost cause) a movement to use the better methods for all purposes, but given that it would be a constitutional change and the errors benefit the already politically powerful, there is pretty much no chance of it happening any time in the foreseeable future.
OTOH, I don't know ow that that actually has anything to do with the chart at issue: there is no information on sources or methodology, just "sources of this data are coming soon". If you don't have the sources ready to cite, you have no business publishing visualizations of the supposed data.
Doesn't make the chart bad... just makes the data a little wonky.
The chart is great. It perfectly represents exactly the data in the tabular form. The data is apparently garbage though.
What you just said doesn't make any sense and is a post-hoc rationalization besides.
The start and end points are the same between the two graphs.
Actually they are not. The starting numbers (1980) differ between the two charts by ~500,000 deaths.
To say that this nitpick throws shade on the entire project is a bit overstated.
My very first search on the data came up with this. I suppose I could have kept searching but that puts me personally at a 100% error rate. Maybe I'm just really really unlucky, though.