Readers write because they want to express a personal opinion, usually about the news. Sometimes tourists or residents will write about their experiences; foreign residents write about things that please or frustrate them; and readers respond to what other readers have written.

Recently, the picture and caption below appeared in the news section of the Bangkok Post. A reader was upset by the picture and wrote to say so. His letter appeared in Postbag two days after the picture.

SELF-DEFENCE IN SCHOOLS A schoolgirl practises a knee thrust with a dummy at Wat That Thong School on Sukhumvit road. The Muay Thai Centre organised a demonstration at the school yesterday as part of Wattana district's pilot project to introduce Thai boxing to schoolchildren. — SOMCHAI POOMLARD

Letter writers may or may not think about what makes a good letter, but thoughtful readers should. Here are some guidelines to help you think about whether today’s letter is effective or not.

Some writers state their opinions very clearly and directly. Others use an indirect or humorous way of making a point. Or, they may actually mean the opposite of what they say. For example, if a writer praises a traffic policeman for keeping the traffic light red long enough for him to finish the book he was reading, you can be sure this is not really praise. Instead it is criticism in the form of satire – making fun of something in order to show that it is bad.

1. Is today’s letter direct, humorous or satirical?
2. What point is the writer of the letter below making? Who is the writer upset with, the newspaper or the school?

A letter cannot be convincing without providing evidence to support the opinions it expresses. Watch particularly for the most emotional letters. Often they provide very little real evidence to support the point begin made. Strong language alone does not make a convincing argument. For example, a writer may attack the character or personality of a previous writer without contradicting anything that writer may have said.

3. Does A concerned parent seem to know what he/she is talking about?
4. Does the writer give reasons to support his or her opinions?

Some writers write letters just for fun. They may seem serious, and propose some very complicated and strange ideas, but they are just trying to make people laugh.

5. Is this a serious or a humorous letter?