The Values in Action Inventory for Youth (VIA-Youth) is a 198 item self-report questionnaire that is very similar to the better known VIA Survey of Character. It was developed by Nansoon Park and Christopher Peterson who first described it, I think, in a paper  in the Journal of Adolescence. The VIA-Youth measures 24 so-called ‘character strengths’  organized under six broad ‘virtues’ and is intended for use with young people aged 10–17 years.
The journal paper  explains that the authors, ‘ with different item formats and phrasings before arriving at the current inventory, which contains 198 items (7–9 items for each of the 24 strengths, placed in a nonsystematic order), about one-third of which are reverse-scored. … Respondents use a 5-point scale to indicate whether the item is “very much like me” (=5) or “not like me at all” (=1). Subscale scores are formed by averaging the relevant items.’ Unfortunately the explanation of the scoring ends there.
I had not heard of the VIA-Youth until yesterday when I was asked, by someone who had seen my earlier blog posting  on the VIA Survey of Character, whether I knew anything about the VIA-Youth scale. I didn’t, but found, amongst other copies, a Master of Science dissertation  that contains a copy of the VIA-Youth. With a knowledge of the 24 character strengths, it is not difficult to infer the scoring key.
There are some differences from the way that the adult scale is scored. Items 1–168 are in seven repeating blocks of 24 questions. Within the 24 item blocks, the Character Strengths are in the same order. However, the items from 169–198 are different. The next block would normally be from 169–192, but in fact it is from 169–191 because the item for the character-strength of “Forgiveness” has been omitted. The remaining 7 questions (192–198) are for the character strengths called Fairness, Humour, Perseverance, Kindness, Love, Humility and Self Regulation.
The other difference between the Youth scale and the adult scale is that all the adult items are scored the same way. However, as Park and Peterson commented in their paper, some of the youth items are scored in the reverse direction. I have provided links to two spreadsheets that describe the scoring key completely. The first spreadsheet is in Open Document format [ODS-link], the other in Microsoft Excel format [XLS-link]. I have indicated in the spreadsheet whether the item is scored in the + direction or the – direction. More clearly, I have indicated whether the responses should be scored 5..1 (meaning that “Very Much Like Me” is 5, and “Not Like Me At all” is 1), or 1..5 (meaning that “Very Much Like Me” is 1, and “Not Like Me At all” is 5).
I expect that having the scoring key readily available will promote greater empirical examination of the scale.
 Dieckman, D. (2009). Locker Room To Life: Do Sports Build Character? Dissertation for the degree of Master of Science in Guidance and Counseling. University of Wisconsin-Stout. [link]
 Diamond, M., O’Brien-Malone, A., & Woodworth, R. J. (2010). Scoring the VIA Survey of Character. Psychological Reports, 107(4), 833-836. DOI: 10.2466/02.07.09.PR0.107.6.833-836
 Park, N., & Peterson, C. (2006). Moral competence and character strengths among adolescents: The development and validation of the Values in Action Inventory of Strengths for Youth. Journal of Adolescence, 29(6), 891–909. DOI: 10.1016/j.adolescence.2006.04.011
 Petersen, C., & Seligman, M. (2004). Character Strengths and Virtues: A Handbook and Classification. Oxford: Oxford University Press.