What is a T-chart?

The shape is the definition

A T-chart (also written t chart or t-chart) is a capital T. The top bar is the shared topic. The vertical stroke splits two columns. Each column is a list: for and against, before and after, claim and evidence, protagonist and antagonist. Items do not sit in both columns. If something honestly belongs in both, you wanted a Venn diagram.

Teachers like it because the page itself prevents a paragraph from wandering. The left column is one idea. The right column is the other. The heading stops the two lists from being about different questions.

Example: a lab report choice

Topic bar: 'Hand-write the lab or type it.' Left column, hand-write: faster to start, sketches sit next to numbers, harder to share with a partner who is absent. Right column, type: easier to revise the conclusion, graphs can be pasted, the bench is a bad place for a laptop. The decision is not inside the chart. The chart is the evidence you read before you choose. A decision tree is the next drawing if the choice has more than one question.

Keep the columns parallel

If the left side says 'cost' the right side should answer cost, not a different virtue. Parallel rows let a reader compare across the stroke. A left column of five items and a right column of one item is still a valid T-chart. It is also a signal that the case is lopsided, which is a finding, not a formatting error.

Steps

1. Write the topic on the bar. One question. 'Which notebook?' is a topic. 'School' is too wide.
2. Name the columns with the same kind of word. Two nouns, or two verbs. Mixing 'cheap' and 'the bus option' makes the rows hard to scan.
3. One item per line. A line that needs a semicolon is two items.
4. Stop when a new row repeats an old one. Repeats are a sign you have enough to decide or to switch diagrams.