Instrument Development

Best Friend Index (BFI)

Friendship Quality

Friendships are a source of love and affection and give a sense of belonging. They are typically characterized by closeness, love and trust (Hruschka, 2010). The older one gets, the more complex the friendships tend to become (De Goede et al., 2009). Being a dynamic relationship, friendship can be seen more as a balance between the good and bad traits and behaviors one may possess.

Looking deeper into this balance, one can identify  both positive friendship qualities (PFQ) and negative friendship qualities (NFQ). Positive qualities include companionship, reliable alliance, disclosure and support, while negative qualities include jealousy, dominance and competition, among others.

The qualities one may associate with a friendship are many, but how do you make sure both the positive and negative qualities are presented equally in academic research? The Best Friend Index (BFI) is developed with the balance between the positive and negative qualities of a friendship in mind. Questions are varied, simple and short, which makes it easy and quick to present it to children.

The positive qualities are taken from the Network Relationship Inventory (NRI; Furman & Buhrmester, 1985; Selfhout, Branje, & Meeus, 2008) and negative features from the Friendship Quality Questionnaire (FQQ; Parker & Asher, 1993). Questions are adapted to be answered on a 5-point scale (1 = Never, 5 = Very Often), with 18-items in total.

  • Original questionnaire

Kouwenberg, M., Rieffe, C., & Banerjee R. (2013). A short and balanced Best Friend Index for children and adolescents. European Journal of Developmental Psychology, 10, 634-641.

  • Other applications

O’Connor, R., Blijd-Hoogewys, E., Stockmann, L., Van den Bedem, N. P., & Rieffe, C. (in press). Friendship quality among autistic and non-autistic (pre-)adolescents: Protective or risk factor for mental health? Autism.

Here you can download different versions of the Best Friend Index (BFI):

The English version:  

Please note that we currently do not have norm scores or cut-off scores for our questionnaires. Read Frequently Asked Questions for more details.