The project was commissioned by British consumer electronics brand Alba, who surveyed 2,013 adults in the United Kingdom on whether they use music to uplift their mood and which feel-good songs they preferred from several decades. To take the results a step further, Alba sought out a researcher that could tinker with the database of responses and output a mathematical formula for the ultimate feel-good song.

Jolij’s final equation of Feel Good Index (FGI) includes the sum of all positive references in the lyrics, the song’s tempo in beats per minute and its key. The higher a song’s FGI, the more feel-good it is predicted to be. Happy lyrics, a fast tempo of 150 beats per minute (the average pop song has a tempo of 116 beats per minute), and a major third musical key all help create music we perceive as brimming with positive emotion.