Table 3.
Predictor variables and interaction terms selected by lasso, with coefficients and statistical significance.
| Initiation | Recent sex | Sex without a condom | |||
|---|---|---|---|---|---|
| Attracted to both male and female gender people × Hispanic | 0.396 | Ever had sex | 0.297*** | Ever had sex | 0.172*** |
| Attracted to both male and female gender people × Mother’s education: Some college or more | 0.0562 | Had sex in the past three months | 0.118 | Had sex in the last three months | 0.0823* |
| Attracted to both male and female gender people × Father’s education: Some college or more | 0.231 | Substance use scale | 0.106 | ||
| White × Substance use scale | 0.519** | Attracted to same-gender people × Knowledge about other contraception | 0.593*** | Father figure present × How many times had sex in last three months | 0.00386 |
| Multiracial × Beliefs about condoms | 0.277** | Substance use scale × Knowledge of pregnancy | 0.292 | Mother’s education: High school or less × Ever had sex | 0.0751** |
| Other race × Attitudes about condoms | −0.342** | In a serious relationship × Refusal skill | 0.0710** | Had sex without a condom in past three months × Knowledge of condoms | 0.101 |
| Mother’s education: Some college or more × Sexting scale | 0.0250 | Grade 9 × Mother figure present | −0.0409* | Substance use scale × Knowledge of pregnancy | 0.460*** |
| Mother’s education: Some college or more × Ever been in a relationship | 0.0215 | Negotiating skill × Ever had sex | 0.0386 | Knowledge of HIV × Ever had sex | 0.0547 |
| Age × Kissing scale | −0.00176 | Number of partners for vaginal sex × Summer between baseline and follow-up | 0.0286*** | Knowledge of condoms × Ever had sex | 0.115 |
| Age × Ever been in a relationship | 0.00327 | Knowledge of condoms × Ever had sex | 0.0266 | Age × Times had sex in past three months | 0.000183* |
| Substance use scale × In a casual relationship | 0.387* | Knowledge of HIV × Ever had sex | 0.0235 | ||
| Substance use scale × Knowledge about condoms | 0.213 | Substance use scale × Knowledge of condoms | −0.00919 | ||
| Substance use scale × Sexting scale | 0.0276 | Had sex in the past three months × Negotiating skill | 0.00500 | ||
| In a serious relationship × Attitudes about condoms | 0.0651 | Knowledge of pregnancy × How many times had sex in last three months | 0.00334 | ||
| In a serious relationship × Kissing scale | 0.0580 | Father figure present × How many times had sex in last three months | 0.00214 | ||
| In a serious relationship × Intent to have vaginal sex in next 12 months | 0.0840 | ||||
| Grade 9 × Summer between baseline and follow-up | −0.0698 | ||||
| Grade 9 × Girl | −0.0488 | ||||
| Knowledge about pregnancy × Touching scale | 0.0844 | ||||
| Beliefs about condoms × Touching scale | 0.174** | ||||
| Attitudes about condoms × Touching scale | 0.0629 | ||||
| Negotiating skill × Sexting scale | 0.117 | ||||
| Negotiating skill × Opportunity scale | 0.000446 | ||||
| Refusal skill × Opportunity scale | 0.102 | ||||
| Sexting scale × Ever been in a relationship | −0.0299 | ||||
| Touching scale × Intent to have vaginal sex in next 12 months | 0.0821 | ||||
| Opportunity scale × Kissing scale | 0.0748 | ||||
| Grade 11 × In a serious relationship | 0.344* | ||||
| Kissing scale × Summer between baseline and follow-up | 0.0699 | ||||
| Girl × Mother’s education: High school or less | −0.0709* | ||||
| Attracted to same-gender people × Online scale | −0.323** | ||||
| n | 833 | 1,294 | 1,282 | ||
| R squared | 0.231 | 0.347 | 0.286 | ||
| Share predicted correctly | 0.801 | 0.812 | 0.846 |
Note: While not shown for brevity and clarity, two cluster variables were selected by lasso for initiation and one for recent sex.