It depends on the standard. Some refer to a fixed skill, while others become more complex over time.
Let's take the Grade 2 report card for example. One of the math standards states, "Tells time to the quarter hour and 5 minute intervals." Once a student is able to do this, they receive an 'M' whether it's in the first quarter or the fourth quarter.
On the other hand, the criteria for meeting some standards especially around phonics, comprehension, and problem-solving become more difficult over the course of the year. For example, one of the language standards states, "Uses phonics skills to decode words." In the first quarter, the class might be working on two-syllable words and long vowels. If a student is able to do this, they would receive an 'M' rating. However, in the third quarter, the bar for reaching an 'M' is higher. The class might now be focusing on more advanced skills such as vowel teams, advanced suffixes, and three syllable words. Similarly in math, students might be focusing on one step problems involving addition and subtraction in October, but might be completing longer two step problems using tables in April.
Of course, if you have any questions about these complexities, don't hesitate to contact your child's teacher.