An Artificial Construction

[ReneZ]

In exercises like these, one always has numerous options, and the combination of each set of options will lead to a different result. In practice, it is tempting to select a single set of options, based on some subjective (or even subconscious) preferences.

What do I mean with that? 
Examples for Pinyin transcribed Mandarin.

Option 1: "how to represent tones"
a) one can simply leave out the tone information. (This is of course a very significant loss of information)
b) one can use the most common 'accent' representation, and thereby end up with multiple vowels
c) one can represent the tone by a separate character
c1) this separate character can be written after the vowel
c2) this separate character can be written at the end of the syllable
(c1 and c2 often coincide)

Option 2: "how to distinguish the two different sounds both represented by 'i' "
a) Follow the Pinyin writing. Both sounds are mapped onto the same character
b) Knowing the simple rule (it depends on the preceding consonant), write them as different characters

Option 3: "how to distinguish the two different sounds represented by 'u' and 'ü' "
a) Ignore the difference. Both sounds are mapped onto the same character
b) Follow the Pinyin writing, which leads to incorrect Mandarin
c) Knowing the rule, write them correctly as different characters
(The rule here is a bit more tricky. Some consonants are always followed by 'u', and 'u' is written.
Some consonants are always followed by 'ü' and then also 'u' is written.
Some consonants can be followed by both, and only then 'ü' is written when it sounds like that.)

This already results in 4x2x3 = 24 combinations, leading to different statistics