Why does significant digits function and round function round down in these examples? Result should be 211, but R outputs 210.

```
signif(x = 210.5, digits = 3)
[1] 210
```

```
round(210.5, digits = 0)
[1] 210
```

Why does significant digits function and round function round down in these examples? Result should be 211, but R outputs 210.

```
signif(x = 210.5, digits = 3)
[1] 210
```

```
round(210.5, digits = 0)
[1] 210
```

I think this is due to a behavior of R rounding to nearest even.

See `?round`

help page

Note that for rounding off a 5, the IEC 60559 standard (see also ‘IEEE 754’) is expected to be used, ‘

go to the even digit’. Therefore`round(0.5)`

is`0`

and`round(-1.5)`

is`-2`

. However, this is dependent on OS services and on representation error (since e.g.`0.15`

is not represented exactly, the rounding rule applies to the represented number and not to the printed number, and so`round(0.15, 1)`

could be either`0.1`

or`0.2`

).

can you suggest how to solve this issue, so the output rounds to the appropriate number?

`ceiling()`

should do the job.

```
ceiling(210.5)
#> [1] 211
```

^{Created on 2020-04-22 by the reprex package (v0.3.0)}

There is a lot of SO questions on this topic, you could see the inspiration for workaround there:

- rounding - Is there an error in round function in R? - Stack Overflow
- r - Round up from .5 - Stack Overflow

There is also this blog post and a solution inspired by one on SO

Hope it helps.

I think you'll find the term "appropriate number" is arbitrarily defined. And a very good case can be made that always rounding up in the case of a 0.5 is not the best approach to rounding.

You'll find that all respectable programs use this same round-to-even standard. I would recommend embracing it.

This topic was automatically closed 21 days after the last reply. New replies are no longer allowed.