I found at the secondary level, it was more effective to work with the students first, then contact parents (or guardians) about misbehavior after exhausting in-house strategies. Even if you typically e-mail or text, having a real-time voice conversation with parents or guardians may be the most effective way to express your concern.
Determine an appropriate time to speak (it may not be possible for all parents to talk while at work) through a text or e-mail. Or ask them to call you and suggesting times, such as early morning or late afternoon. (It’s a good idea in your welcome letter at the beginning of the year to ask parents the best way and time to communicate.)
Prepare notes to help stay focused on the problem and what you want to discuss.
Start with some positive comments about the student and emphasize you want what’s best for their child to be a successful learner. Provide examples of the behavior in question and how you tried to correct the situation. Ask for other ideas on how you can work together to resolve the issues. If the disruptive behavior occurs during a lab activity, remind the parents of the safety acknowledgement form they signed.
Give the parents time to respond and listen to them without interruption, using wait-time before you respond).
You can ask your mentor or administrator to be present (be sure to mention that he/she is there).
At the end, summarize what you and the parents will do and expectations for the student. Thank them for their time and input. Follow up on the conversation with any results.
Annotate your notes and keep a log of your communications.