**Answer**

The Youngster achievement is actually awarded for catching some number of Rattata below a certain weight.

The achievement previously stated “Caught {0} Rattata weighing at most {1}”. In many programming languages, `{0}`

and `{1}`

are just ways to substitute numbers into some text. It seems that Niantic simply messed up the description, even though it tracks correctly.

A screenshot may be found at Timelord64’s answer to the question I’ve got an “XS” Pokémon. Is it special?, reproduced here:

The badge is called `BADGE_SMALL_RATTATA`

in the data dump. The data dump lists its targets as `\0032\254\002`

, which translates to requirements of 3, 50, and 300. There’s no indication for weight, but I suspect it just requires XS Rattata.

Regarding XS Rattata specifically, I hypothesise that a Rattata is XS if it is 2 standard deviations below the mean. The mean for Rattata is 3.5 kg, and the standard deviation is 0.4375 kg, so you should be getting it for Rattata below 2.625 kg. (The game only shows two digits for weight, so this falls between 2.62 and 2.63 kg. I hypothesise this because I have a 2.4 kg XS Rattata, and a 2.75 kg regular Rattata.)

**Attribution***Source : Link , Question Author : Insane , Answer Author : Community*