In an English class taken by my friend's son, a seventh-grader, late assignments are lowered a full letter grade. Last term he handed in a paper. His parents saw him write it, his peers saw him deliver it, but his teacher, who previously lost one of his assignments, said she did not receive it. She acknowledged "the possibility of human error on either side" and so "split the difference," lowering the grade half the usual amount, to a B instead of a B-minus. Fair? -- J.E., Brooklyn, N.Y.

This is a poor resolution to the problem, one wisely eschewed in criminal trials. A judge and jury may not conclude: There is no proof that you are guilty, but we have our suspicions, so we'll split the difference between acquittal and the maximum penalty and give you seven years.

The parents saw the paper. The boy says he handed it in. His peers remember his doing so. The teacher previously lost one of his papers. These things do not prove the boy's claim, but they bespeak too much uncertainty to penalize him. And the teacher's proposed compromise suggests that she herself is unsure of the facts. (One step that might support the boy's claim that he wrote the paper, at least: Is there a saved copy of the paper on his computer?)

The standard of proof in a classroom is not that of a courtroom. Teachers should have wide latitude in grading. But they have a concomitant obligation to take prudent steps to avoid error. For a grading system to be fair, it must be ably administered. Did this teacher meet that standard? It's hard to know in a case of student said, teacher said. But a high school teacher I consulted summarized the situation this way: "The lesson about not handing things in late is a good one, but only if employed accurately. The teacher could keep track of this with a checklist in her grade book."

Or she could hand out receipts -- the cashier's approach, rather than that of the courtroom -- and thereby shift the burden of proof to the students.

A woman I hired to do simple gardening comes weekly and, when school is out, brings her kids. While her twin preschoolers play in the shade, her approximately 9-year-old daughter works alongside her. I am uncomfortable watching my 8- and 11-year-old boys kicking a soccer ball as the girl walks past pushing a wheelbarrow. Should I ask the mother to keep her daughter from working? Should I not employ this woman? -- Jane E., Albuquerque, N.M.

You are rightly dismayed by this situation, but you've phrased the question curiously, emphasizing your discomfort rather than a child's well-being. If you are concerned about the daughter, as you admirably seem to be, you ought not make her life harder, which firing her mother would certainly do. And rather than insist that the mother make the daughter drop that wheelbarrow, you might encourage your sons to invite the daughter to play soccer with them. Her mother will likely be relieved: Having a 9-year-old "help out" all but guarantees the task will take longer.

It would be commendable if you could proffer some practical advice. Presumably this woman brings along her children because she has no alternative. Does your town offer inexpensive day-care programs? Are there other social services that might benefit her three kids? A bit of time on the phone or online might lead you to something that helps this family and eases your own mind.

UPDATE: The gardener failed to show up a few times, and Jane "used that as an excuse" to find someone else for the job.