How to grade with partial credit

Start with points, not just wrong answers

Counting wrong answers works when each question has the same value and answers receive either full credit or none. Partial credit changes that shortcut: a question might earn half a point, while a multi-step problem might earn three points out of five.

Before calculating, identify the maximum points for every question. Add the awarded points, including fractional marks, and divide by the assessment’s total possible points. Keep the marking decisions separate from the percentage calculation.

Work through a small assessment

Suppose an assessment is worth 20 points. A learner earns 17.5 points after partial marks are awarded. The percentage is 17.5 ÷ 20 × 100 = 87.5%. In the easy grader, choose Points earned, enter 20 possible and 17.5 earned.

For 25 equally weighted one-point questions, losing 3.5 points leaves 21.5 earned points. The result is 86%. You can enter 3.5 in the number-wrong/points-lost mode because that field represents the points lost, not necessarily a literal count of completely wrong answers.

Handle unequal question values

Imagine an assessment containing ten one-point questions and two five-point problems. The total is 20 points. Missing a five-point problem has a different effect from missing a one-point question. Entering one wrong answer out of twelve would produce the wrong percentage.

Use points mode for this assessment. For a printed reference, generate a chart based on the total points and treat the wrong-count column as points lost. Label your printed copy so another marker can tell how it should be used.

Write a marking rule that another teacher can apply

For a five-point explanation, you might assign one point for identifying the relevant idea, two for using appropriate evidence and two for connecting that evidence to the conclusion. A response that identifies the idea and explains one relevant piece of evidence might earn 1 + 1 + 1 = 3/5. The decision comes from the stated criteria, not the calculator.

If half-points are permitted, say what earns them. For example, an explanation that makes a relevant connection but leaves a necessary step implicit might receive 1.5 of the two reasoning points. Use a few anonymous sample responses to check that the marking rule is understandable before applying it to the full assessment.

For the table above, enter 17.5 earned and 20 possible in points mode. The result is 87.5%. Do not divide 17.5 by the twelve questions: the number of questions and the number of available points describe different things.

Make repeated marking consistent

Decide which evidence earns partial marks before working through the assessment, and record those decisions in a marking guide or rubric. If you revise the rule, review previously marked work so the calculation has a consistent basis.

• Keep fractional marks until the final calculation.
• Apply any rounding rule at the stage specified by your course policy.
• Use a custom letter scale only after checking the required thresholds.
• Treat extra credit as an explicit policy rather than silently capping scores.