Table 1 Definitions of variables, questionnaire items and analytic coding

Sex and gender

 Assigned sex at birth

An individual’s biological status as male, female, or something else, which is associated with physical attributes, such as anatomy and chromosomes

What is your sex?

Assigned female at birth vs assigned male at birth

 Sexual orientation

One’s enduring sexual attraction to male partners, female partners, or both

Which of the following best describes you?

Heterosexual, gay or lesbian, bisexual, not sure

 Gender expression

The manner in which an individual chooses to present their gender to others through physical appearance and behaviors, e.g., style of hair or dress, voice, or movement

A person’s appearance, style, dress, or the way they walk or talk may affect how people describe them. How do you think other people at school would describe you?

Gender conformity vs gender nonconformity

 Gender identity

An individual’s sense of their self as male, female, transgender, or something else

Some people describe themselves as transgender when their sex at birth does not match the way they think or feel about their gender. Are you transgender?

Cisgender, transgender, not sure

School bullying

 Traditional bullying

Physical bullying (e.g., hitting, pushing, and kicking), verbal bullying (e.g., name-calling and teasing in a hurtful way), and relational bullying (e.g., social exclusion and spreading rumors)

During the past 12 months, have you ever been bullied on school property?

Yes vs no

 Cyber bullying

An extension of traditional bullying that performed via electronic means such as mobile/cell phones or the internet

During the past 12 months, have you ever been electronically bullied? (Count being bullied through texting, Instagram, Facebook, or other social media.)

Yes vs no

 Combined bullying

Traditional or cyber forms of bullying

Computed variable: being bullied traditionally or electronically during the past 12 months

Yes vs no