I added an informative text to a tag which had no excerpt. (click to see the case, should be publicly available)

To me this seems a reasonable excerpt which is not superfluous, not harming readability. I would even say it informs users of the usage of the tag. The tag in question is the '20th century language' tag, so I added in the excerpt '1900-1999' and some added text to make it readable. In response, I seem to have received a rather standard answer, which does not tell me why this would be a bad proposal:

"This edit does not make the post even a little bit easier to read, easier to find, more accurate or more accessible. Changes are either completely superfluous or actively harm readability."

It would be very informative to properly tell users why a proposed edit is bad, otherwise they will make the same mistake (if it actually was one) again. Please provide me (and others) with this information.

  • 3
    If you submit it with the correction, I'll approve it.
    – tchrist Mod
    Commented Mar 17, 2018 at 17:08
  • Only if you start counting the years from 1BC and mark the 1st century as 1BC-99, the 20th century would be 1900-1999.
    – user370931
    Commented Jun 14, 2020 at 7:20

2 Answers 2


The Twentieth Century ran from 1901–2000, not from 1900–1999. :)

  • 6
    Because that's not how language works. There is no year 0. The first year of the first century was the year 1 not the year 0. You also don't get to vote on math. :)
    – tchrist Mod
    Commented Mar 17, 2018 at 17:13
  • 2
    @JJJ That's nice. You don't get to vote on how other people speak or think, no matter what ISO V̅MMMDCI may say.
    – tchrist Mod
    Commented Mar 17, 2018 at 17:18
  • 1
    @JJJ People use words the way people use words, and the 20th Century has always meant 1901–2000. We aren’t passing a law telling them they’re wrong when in fact they are indeed mathematically correct and it’s the people who don’t understand ordinals who are wrong. What’s next, voting that a pound is half a kilogram instead of sixteen ounces, or for the acceptability of singular they?
    – tchrist Mod
    Commented Mar 17, 2018 at 17:24
  • 4
    @JJJ While life would be a whole lot easier if every software and firmware developer on the planet adhered to ISO 8601 instead of trying to do their own thing (and failing miserably at it), the purpose ISO 8601 is not to define English vocabulary - it's completely irrelevant here. It's well known that "The Twentieth Century" means 1901-2000. Whether or not the standard for communicating date/time information wants a zero-based index or a one-based index doesn't change the English name of the century.
    – ColleenV
    Commented Mar 17, 2018 at 17:34
  • @tchrist - new tag excerpt created.
    – user370931
    Commented Jan 18, 2020 at 6:13
  • 2
    @tchrist re this comment. I like how two of your three predictions seem to have been accepted since (at least here on SE). Last year, pronouns were a hot topic on meta, and singular they seems to be the favorable starting point now. Yesterday, SE's digital marketing manager celebrated the new decade. You may have a gift here. Be careful what you wish for (or against), literally. ;p
    – JJJ
    Commented Feb 20, 2020 at 11:39
  • @JJforTransparencyandMonica they should probably take down that blog post and rewrite/reupload it on 2021, which is the next year.
    – user370931
    Commented Feb 23, 2020 at 12:58
  • 1
    @JJforTransparencyandMonica, It says a "new decade", not the "203rd decade, CE", which won't start until 2021. It's okay to say that the '60s decade ran from 1960 through 1969. No one, even the most pedantic, would claim that 1970 is part of the '60s. (Actually that's not quite true, for me at least, the '60s started with the JFK assassination and the Beatles and continued until Watergate and disco.) Commented Jun 14, 2020 at 12:44

For your follow-up question:

When did this century start? 2001 or 2000?

The answer is yes.

It's up for a debate - the 21st century started on 2000 or 2001.

You say:

I would argue to follow the ISO 8601 standard. That way, decades are associated with centuries, so the first decade of this millennium (2000-2009) is entirely in the 21st century, rather than being split over the 20th and 21st.

Here's an example question: Did the 2000s decade run from 2000-2009 or 2001-2010?

Again, the answer is yes.

If you start counting from 1BC, the 0s decade (first AD decade) contains the years 1BC, 1, 2, 3, 4, 5, 6, 7, 8, 9. This makes 10 years. Then the 2000s decade contains the years 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009. Again, 10 years.

However, if you start counting from 1, the 0s decade then contains the years 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. We still have 10 years. The 2000s decade then contains the years 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010.

A century is a period of 100 years - which means it has 10 decades. If you start counting from 1BC, the 1st century will be made of:

  • 0s (1BC-9)

  • 10s (10-19)

  • 20s (20-29)

  • 30s (30-39)

  • 40s (40-49)

  • 50s (50-59)

  • 60s (60-69)

  • 70s (70-79)

  • 80s (80-89)

  • 90s (90-99)

If you start counting from 1:

  • 0s (1-10)

  • 10s (11-20)

  • 20s (21-30)

  • 30s (31-40)

  • 40s (41-50)

  • 50s (51-60)

  • 60s (61-70)

  • 70s (71-80)

  • 80s (81-90)

  • 90s (91-100)

Then the 20th century ran from 1900-1999 if you start counting from 1BC, or from 1901-2000 if you start counting from 1. The 21st century runs from 2001-2100 if you start from 1, or from 1BC, 2000-2099.

The ELU community appears to define decades, centuries, and millenniums as one-indexed (years are counted from 1) rather than zero-indexed. I prefer to count starting from 1 as well, but if you want to start counting from 1BC, then it's your choice - but, take it elsewhere.

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