What level of measurement are names by letters? A respondent had to correctly recall the name of a character from the scenario. Both the first and the last names consisted of 5 letters each. For each letter, the respondent would get 0.2 points. If the respondent got correct the full first name of the character, the respondent would be awarded 1 full score. If the respondent got both the first and the last names right, the respondent would be awarded 2 full scores. 
In this context, what is the level of measurement of the data derived from such question? In addition, what would be the appropriate test to use for determining and comparing averages of the respondents' performances on the question?  
 A: It is somewhat hard to understand what you asking, as your question does not even have a superficial explanation of what you're after. But if you question is simply about the measurement scale of the outcome variable, it's not so difficult.
Your outcome is a count variable. (At least if I get you right that the respondent also gets 1 full score if he gets only the last name right). Though you seem to count not in steps of 1 but of 1/5... This is still a count variable. That means your scale is superior to an ordinal scale at least. 
Wikipidia can help you figuring out what scale exactly this implies. If you want to rely on Steven's classification your scales would be a ratio scale (Nominal, Ordinal, Interval, Ratio). You have a natural zero, as you're just counting something. Put verbally your scale measures "How many of the letters are remembered by the participant", and you are able to make statements such as "Participant A remembered twice as many letters as participant B". With an interval-scale you'd only be able two make statements such as "Participant A remembered XYZ more than participant B"
Your problems with this (i.e. the natural max) indicate that there could be finer (or altogether different) classifications of scales. 
