Revise comparisons so that both subjects are evaluated using the same criterion and comparable details.
The principle: keep the criterion the same
A comparison is parallel when you judge both subjects by the same standard. A criterion is the feature you use to judge them, such as ease of use, cost, clarity, or time required. If you compare one option’s convenience with another’s appearance, readers cannot tell which option performs better on a shared measure. The details may be true within your example, but the comparison does not answer one consistent question. Before drafting or revising, state the criterion in a short phrase: “ease of carrying,” for instance. Then make sure each subject has evidence relevant to that phrase.
In the margins Why this passage works +
“A criterion is the feature you use to judge them”
This defines the central decision writers need to make before comparing details.
A quick method for checking
First, name the two subjects. Second, identify what the paragraph says about each one. Third, ask whether both details answer the same question. If they do not, either choose a different criterion that fits both details or replace one or both details. Keep the comparison at a similar level of specificity: a concrete observation about one subject is hard to weigh against a broad impression about the other. Finally, state what the matched details show. A parallel comparison does not require the subjects to be alike or to have equal strengths; it requires the basis for judging them to stay consistent.
Worked demonstration
The following example is fictional. Imagine a student comparing two ways to carry class notes: a paper folder and a tablet. The original paragraph says: “The folder is easy to carry because it is thin. The tablet is useful because it can store many files.” The details describe different advantages. “Thin” relates to portability, while storing many files relates to capacity. The reader cannot decide which method is easier to carry from those points. To make the comparison parallel, keep portability as the criterion and describe how each option fares on that measure. For example: “The folder is easy to carry because it is thin and light. The tablet is also easy to carry because it replaces a stack of folders, though it needs to be charged.” Now both subjects are considered in terms of carrying them. The charging detail adds a relevant limitation: it concerns what is needed to take the tablet along and use it. If the paragraph’s goal were instead to compare storage capacity, the writer could choose that criterion and provide a storage detail for each subject.
In the margins Why this passage works +
“both subjects are considered in terms of carrying them”
The revision works because both details now address the shared criterion of portability.
Revise, then check the reasoning
When you revise, do not simply make the sentences sound more balanced. A matching sentence pattern can still compare unlike qualities. Underline the criterion in your topic sentence, then label each supporting detail with the question it answers. If the labels differ, revise the evidence or narrow the claim. Afterward, read the paragraph as a reader: can you explain what standard was used and what the comparison establishes? Avoid claiming that one subject is “better” unless the paragraph says better for what purpose. A careful comparison can conclude that one option fits a stated need more closely while acknowledging a trade-off.
In the margins Why this passage works +
“can you explain what standard was used”
This reader-focused question checks that the comparison's basis is explicit, not merely implied by sentence structure.
Practice
This fictional exercise compares two ways to plan a group project. Revise the sentences so both methods are judged by the same criterion, and state what the comparison shows: “A shared paper calendar is easy to see because it hangs on the wall. A phone reminder is convenient because it can make a sound.” Choose one criterion that can reasonably be applied to both methods. In your answer, make the evidence for each method comparable and avoid claiming that either method is best for every group.
The revision, explained
A shared paper calendar is easy to see because it hangs on the wall. A phone reminder is convenient because it can make a sound.
For visibility, a shared paper calendar is easy for the group to see when it hangs in a common space. A phone reminder is visible to the person holding the phone, but the rest of the group may not see it. By the criterion of visibility to the whole group, the calendar communicates the plan more broadly.
The original pairs visibility with convenience, so it does not establish which method is more visible. The revision names visibility as the criterion and describes each method in relation to the same audience: the whole group. Its conclusion is limited to that criterion rather than asserting that a calendar is universally better. The example is fictional.
Try the idea.
Revise this fictional comparison using one shared criterion: “A shared paper calendar is easy to see because it hangs on the wall. A phone reminder is convenient because it can make a sound.” Explain what your comparison shows without claiming one method is best in every situation.
See the self-check +
For visibility to the whole group, a shared paper calendar is easy for everyone to see when it hangs in a common space. A phone reminder may be visible only to the person holding the phone, so it does not communicate the plan to the whole group as directly. By this criterion, the calendar makes the plan more visible to the group. Self-check: both details address visibility to the same audience, and the conclusion is limited to that standard.