Horizontal alignment refers to the coordination of educational goals, standards, and assessments across different grade levels or subjects within the same educational system. This ensures that students receive a consistent and coherent learning experience, allowing them to build on their knowledge progressively as they advance through their education. In practice, horizontal alignment involves collaboration among teachers and curriculum developers to create a unified approach to instruction. For example, if math skills are taught in third grade, they should be reinforced in fourth grade to ensure students have a solid foundation before moving on to more complex concepts.