- Erection Hardness Score (EHS). The EHS has a single Likert scale, and the validated Spanish version will be used (27). The score is as follows: 0 = Penis does not increase in size; 1= the penis increases in size but is not hard; 2 = the penis is hard but not hard enough for penetration; 3 = the penis is hard enough for penetration but not completely hard; 4 = the penis is completely hard and fully rigid (Appendix 1).