| Phi Value | Relationship strength | Phi Value | Relationship strength |
| +0.70 or higher | Very strong positive relationship | −0.70 or higher | Very strong negative relationship |
| +0.40 to +0.69 | Strong positive relationship | −0.40 to −0.69 | Strong negative relationship |
| +0.30 to +0.39 | Moderate positive relationship | −0.30 to −0.39 | Moderate negative relationship |
| +0.20 to +0.29 | weak positive relationship | −0.20 to −0.29 | weak negative relationship |
| +0.01 to +0.19 | No or negligible relationship | −0.01 to −0.19 | No or negligible relationship |
| 0 | No relationship | 0 | No relationship |