Writing a lesson plan helps a teacher think through a lesson ahead of time and do a mental dry run to anticipate student responses, questions and misunderstandings. This allows the teacher to plan responses and alternate activities or explanations as back up if the lesson isn't going as planned. They can also consider how this particular lesson fits into the goals for an entire unit of study and narrow the planned activities to those that serve specific purposes intended for this lesson. In short, a lesson plan clearly defines what a student should learn or be able to do and provides a road map for how the teacher will guide her to the goal.
State and district curriculum goals may look like a giant block of information overload when viewed as a composite whole. But writing a lesson plan can help a teacher break down the required learning objectives into manageable chunks and match them with appropriate activities that are suitable to the current achievement level of the students. A well-designed lesson will take into account a student's skill in order to plan the next logical instructional step to keep him moving along the educational continuum for the given subject.
By planning ahead and preparing materials in advance, the teacher projects an air of competence that inspires student confidence in her ability to guide the learning process. When the teacher has a plan and knows where the lesson is going and how to get there through all the unpredictable twists and turns of student thinking and behavior, the instruction will flow smoothly from one activity to the next. The natural rhythm of a well-planned lesson optimizes a student's opportunity to master the learning content.
An old bit of wry humor jests, "If I don't know where I am going, how will I know when I get there?" When teaching a lesson, a critical question for the teacher is how to know when the student has achieved the goal and is ready to move on. Teachers should write lesson plans that clearly define specific learning outcomes and make it easy to assess when students have met the criteria laid out in the objectives. Having specific assessment goals in mind helps a teacher match the lesson activities to the behavior that will be required in the assessment.
One of the simplest purposes for writing a lesson plan is just to communicate to yourself your thought process as you planned the lesson. Like anyone else, teachers have busy lives and a lot on their minds. So what may seem like a great lesson at 8:00 on Sunday night, can slip away in the mind never to be seen again if the teacher does not write out an outline of what she plans to do at 9:00 Monday morning. It should also be written in specific enough detail, that if you are unexpectedly unable to teach on that day, a substitute can easily understand what you were planning and take up where you left off without a hitch.
Principals periodically review their teachers' lesson plans during evaluations. So the plans should give clear evidence of a teacher's professional development and ability to customize lessons to meet the needs of a wide range of student abilities while still meeting the expectations of the required curriculum goals. If the school is stressing the use of a particular method or focusing on improving student achievement in a particular subject, the lesson plan should reflect the teacher's use of ideas and techniques covered in inservice workshops and classes sponsored by the school or district. If a teacher makes post-lesson notes about what went well and what to change next time, it can make for a productive post-evaluation discussion that helps a teacher continue growing professionally.