Why is it necessary to test and re-certify school workers for their pedagogical skills on a regular basis?

State the thesis and your position.
(Everyone should join the military for a two year term once they reach their 28th birthday)
Discuss other viewpoints on the issue.
Offer facts and details supporting your position.
(You should intersperse the facts and details with commentary. Remember, this is primarily a commentary/opinion piece)
If you are able, offer up a solution or resolution to the issue.
Your paragraphs should be well constructed and organized to lead the reader through the essay and ending with your solution/conclusion.