Effort Based Grading Strategy

Inspired by the concept that zero's, especially in assessments, are more detrimental than accurate, I've been using a grading system for assessments (tests, quizzes, etc.) in which students receive 50% of their points from trying problems and the remaining 50% from correct answers. For example, on a 110-point quiz I just gave, students received a maximum of 55 points for their "effort" grade and 55 points for their actual score.

For me, effort is measured binarily; students will only get effort points if I can visibly see that they attempted the problem. A better system would give students partial effort points and would also weight "effort" differently for questions of differing levels of rigor.