Every MYP course, and the Personal Project has a set of assessment criteria. This assessment criteria is how you are graded in the MYP. You are supposed to have MYP assessments that utilize these assessment criteria throughout the year. I have added the assessment criteria for science below. Each class has 4 criteria and the score you can received is in a range 0-8. This is criteria based grading, so a score of 4 does not mean you received a 50%, it is actually a pretty good score.
At the end of each year, all of your assessment scores are utilized to determine your final MYP grade in a class. That scale is 1-7...I know...why? I included a short video explaining the difference between the assessment score and the final grade. Please watch it, it is pretty quick. It is the final grades that are utilized to determine if you get the MYP stole after the Personal Project.