How to calculate the average score?

[nelsonmestevao]

At the moment, the score is an arithmetic average. What are the alternatives to make this as fair as possible?

[CarlosHSF99]

We could remove outliers to mitigate the effect of participants purposefully voting lower than they think the performance deserves to manipulate the final score in their favor. Outliers would be calculated with the use of a quartile method.

Performers should not be able to vote in their performance.

Every performance should be voted, more or less, by the same people as to ensure that performers won't have more (probably inflated) votes just because they have more friends voting. Not sure how to implement this... we could remove all votes from a participant that failed to vote in a predefined percentage of the performances.

[nelsonmestevao]

The number of voters is already very small (less than 50) and that is a concern for me (remove votes from an already low pool). I also think the number of votes is very different from each performance, since the number of elements in the Karaoke changes through the night and even their focus on the performances (I will bring some stats to corroborate these claims).

[nelsonmestevao]

@CarlosHSF99 there you go (my analysis can be found here):

# Team, Song, N.º of Votes, Score
[
  {"Solo (André Mota)", "La Bomba", 30, #Decimal<9.47>},
  {"Solo (Júlio Pinto)", "The Villain I Appear to Be", 29, #Decimal<8.41>},
  {"Shrek is Love?", "Holding Out for a Hero - Single Version", 29, #Decimal<7.45>},
  {"Os Melados", "Amanhã De Manhã", 28, #Decimal<5.86>},
  {"Solo (Diogo Pereira)", "Cavalos de corrida", 27, #Decimal<5.93>},
  {"Solo (Rita Lino)", "Goodbye", 24, #Decimal<6.88>},
  {"Seat Ibiza 1.6 sdi", "Nobody's Perfect", 24, #Decimal<4.13>},
  {"Vou agora ao Intermarche", "Blank Space", 21, #Decimal<8.05>},
  {"Sir.", "Numb", 21, #Decimal<8.24>},
  {"Petitos Patatis Volume 2", "Y.M.C.A.", 21, #Decimal<5.05>},
  {"Seat Ibiza 1.6 sdi", "Running in the 90's", 20, #Decimal<4.10>},
  {"Petitos Patatis Volume 2", "Boss Of Me", 19, #Decimal<3.68>},
  {"Solo (Sofia Gomes)", "If I Ain't Got You - Piano & Vocal Version", 0, 0},
  {"Solo (Carlos Ribeiro)", "Heaven", 0, 0},
  {"Sir.", "Deixa Acontecer", 0, 0},
  {"Shrek is Love?", "I'm a Believer - 2006 Remaster", 0, 0},
  {"Seat Ibiza 1.6 sdi", "Playback", 0, 0},
  {"Seat Ibiza 1.6 sdi", "Fortunate Son", 0, 0},
  {"SH", "Pica Do 7", 0, 0},
  {"SH", "Somewhere Only We Know", 0, 0},
  {"Petitos Patatis Volume 2", "Nobody Likes The Opening Band", 0, 0},
  {"Petitos Patatis Volume 2", "Can't Fight This Feeling", 0, 0},
  {"Patati petitos", "Sincerely, Me", 0, 0},
  {"JNPR", "Red Like Roses, Pt. 2", 0, 0},
  {"IDREP", "Sou Português Emigrante", 0, 0}
]

[nelsonmestevao]

@CarlosHSF99 I have tried to follow your algorithm. I got the following results:

# Team, Song, N.º of Votes, Score, Score without outliers
[
  {"Solo (André Mota)", "La Bomba", 30, #Decimal<9.47>, #Decimal<9.86>},
  {"Solo (Júlio Pinto)", "The Villain I Appear to Be", 29, #Decimal<8.41>, #Decimal<8.68>},
  {"Shrek is Love?", "Holding Out for a Hero - Single Version", 29, #Decimal<7.45>, #Decimal<7.45>},
  {"Os Melados", "Amanhã De Manhã", 28, #Decimal<5.86>, #Decimal<5.86>},
  {"Solo (Diogo Pereira)", "Cavalos de corrida", 27, #Decimal<5.93>, #Decimal<5.93>},
  {"Solo (Rita Lino)", "Goodbye", 24, #Decimal<6.88>, #Decimal<6.88>},
  {"Seat Ibiza 1.6 sdi", "Nobody's Perfect", 24, #Decimal<4.13>, #Decimal<4.13>},
  {"Vou agora ao Intermarche", "Blank Space", 21, #Decimal<8.05>, #Decimal<8.05>},
  {"Sir.", "Numb", 21, #Decimal<8.24>, #Decimal<8.24>},
  {"Petitos Patatis Volume 2", "Y.M.C.A.", 21, #Decimal<5.05>, #Decimal<5.05>},
  {"Seat Ibiza 1.6 sdi", "Running in the 90's", 20, #Decimal<4.10>, #Decimal<4.10>},
  {"Petitos Patatis Volume 2", "Boss Of Me", 19, #Decimal<3.68>, #Decimal<3.68>},
  {"Solo (Sofia Gomes)", "If I Ain't Got You - Piano & Vocal Version", 0, 0, 0},
  {"Solo (Carlos Ribeiro)", "Heaven", 0, 0, 0},
  {"Sir.", "Deixa Acontecer", 0, 0, 0},
  {"Shrek is Love?", "I'm a Believer - 2006 Remaster", 0, 0, 0},
  {"Seat Ibiza 1.6 sdi", "Playback", 0, 0, 0},
  {"Seat Ibiza 1.6 sdi", "Fortunate Son", 0, 0, 0},
  {"SH", "Pica Do 7", 0, 0, 0},
  {"SH", "Somewhere Only We Know", 0, 0, 0},
  {"Petitos Patatis Volume 2", "Nobody Likes The Opening Band", 0, 0, 0},
  {"Petitos Patatis Volume 2", "Can't Fight This Feeling", 0, 0, 0},
  {"Patati petitos", "Sincerely, Me", 0, 0, 0},
  {"JNPR", "Red Like Roses, Pt. 2", 0, 0, 0},
  {"IDREP", "Sou Português Emigrante", 0, 0, 0}
]

Most of the cases, it does not change the score and the ranking is exactly the same.

[nelsonmestevao]

I guess we can conclude that if the people vote fairly, we get the same result as the arithmetic mean, otherwise the results can change a little. In this case, they only went up, but would happen otherwise as well.

[nelsonmestevao]

Implemented in PR #14 🎉