CogAT Grade 2 common mistakes
CogAT Grade 2 · Understand the traps and how to avoid them.
Choosing the answer that sounds nicest or most familiar instead of the one that completes the stated relationship (for example, picking 'dog' for 'cat is to kitten as dog is to ___' because puppies are cute, not because the analogy demands 'puppy').
Young children reason from personal associations and stories rather than from the abstract relation the item tests. The familiar word feels right, so the child stops evaluating the analogy's structure.
What to do instead
Teach a two-step routine the child says aloud: 'First I say the relationship in a sentence - cat is a grown-up kitten. Then I find the pair that does the same job.' Practice with 10–15 oral analogies a day using everyday pairs (cup/glass, sock/foot) and require the child to justify with 'because' before pointing to an answer.
Treating a classification item as 'which one do I like' or 'which one is biggest' rather than finding the single attribute all the others share, so the child picks an odd one out that is odd for a personal reason (favourite animal, scariest item).
Grade-2 children are still developing the habit of searching for a common category. Without an explicit instruction to name the shared feature, they default to preference-based or salience-based choice.
What to do instead
Use a 'name the group first' script: cover the answer choices, name the category of the majority ('these are all things you wear'), then uncover and eliminate. Drill with picture cards sorted into categories the child names out loud, and occasionally include an item that belongs to two categories so the child learns to check every option before deciding.
Answering only the first half of a two-part verbal item - for instance, picking a word that fits the first blank of a sentence-completion or the first pair of a double analogy and ignoring the second constraint.
Working memory and item-reading stamina are limited at this age; the child latches onto the first satisfying match and stops scanning, especially when the test is timed by the group administrator.
What to do instead
Train a 'check both parts' habit with a physical cue: the child touches the first blank, says the word, then touches the second blank and says 'does it still make sense?' Provide practice items with two blanks and two plausible first-blank answers, so the child experiences the need to test the whole item.
Counting on fingers or counting objects one by one when the item asks for a comparison or a 'how many more' relationship, running out of time or losing track mid-count.
Children this age are transitioning from concrete counting to number sense. Under time pressure they revert to the most reliable but slowest strategy, and they miscount when items are pictured in scattered arrangements.
What to do instead
Build subitising and benchmark fluency: daily 5-minute drills recognising quantities to 20 without counting, plus 'how many more to make 10' and 'which is more' games with cards. Teach crossing-out or grouping-by-twos as a faster count for pictured sets, and rehearse the same skill with a 30-second timer so speed is practised, not just accuracy.
Applying the visible arithmetic operation to every number in a pattern instead of finding the rule that actually generates the sequence (for example, adding 2 to 3, 5, 7 and then continuing to add 2 when the pattern switches to +3).
Pattern items often change rule partway or use two interleaved rules. A child who finds one working step assumes it continues forever and does not verify against the next term.
What to do instead
Teach the 'test the rule on the next number' check: after guessing a rule, the child must apply it to the following term and confirm it matches before predicting. Practise short sequences with a deliberate rule change and have the child say the rule aloud ('plus 2, plus 2, now plus 3').
Ignoring units, labels, or the question's final wording in word problems - computing 8 − 3 when the question asks how many altogether, or giving a number with no reference to what it counts.
Grade-2 readers decode slowly, so they often read the numbers and skip the sentence that states the operation. The last sentence, which usually carries the question, is the most likely to be skipped.
What to do instead
Use a read-twice protocol: first read for the story, second read to underline the question word ('altogether', 'left', 'more'). Have the child restate the question in their own words before computing, and answer in a full sentence ('There are 11 altogether') so the meaning of the number is always attached.
Choosing an answer based on overall visual similarity or colour rather than the specific transformation asked for - for example, picking the figure that looks most like the prompt in a paper-folding item instead of mentally unfolding it.
Perceptual matching is the default strategy for young children; the transformation (folding, rotating, reflecting) requires holding and manipulating an image in working memory, which is effortful and easy to skip.
What to do instead
Have the child physically act out transformations with paper and cut-outs before doing them mentally: fold real paper, punch holes, unfold, and compare. Then move to drawing the predicted result before looking at the options, so the child commits to a mental model rather than recognising a familiar shape.
Assuming a rotated figure is a different figure, or that a mirrored figure is the same as a rotated one, when selecting matches in a rotation or reflection item.
Children often treat any change in orientation as a change in identity, and mirror versus turn is a subtle distinction that is not usually taught explicitly before this age.
What to do instead
Practise with a physical shape and a small mirror: turn the shape and note that it still matches the original; mirror it and note that it does not. Use a 'same or different' sorting game with rotated and reflected versions of the same figure, and teach the landmark check - track one distinctive corner or notch through the turn.
Losing the pattern in matrix or series items by looking at only one row or one attribute, then choosing an option that fits that row but breaks the other (for example, matching shape but not shading or count).
Matrix items combine two or three rules at once. A child who finds one rule feels finished and does not scan the columns, and the extra attributes are easy to overlook under time pressure.
What to do instead
Teach a fixed scan order: 'across, then down, then check the missing corner.' Have the child state each rule separately ('the shapes go circle, square, triangle; the colours go dark, light, dark') and cross out any option that breaks even one rule. Begin with two-attribute matrices and add a third only when the two-rule scan is automatic.
Rushing to finish because a neighbour or the group has moved on, leaving items blank or answering randomly at the end of a section rather than returning to skipped items.
Group-administered tests move at an adult's pace, and Grade-2 children compare themselves to peers. Anxiety plus an unfamiliar answer sheet leads to skipped bubbles and no review pass.
What to do instead
Rehearse the full test routine at home: same timing, same 'stop' signal, same instruction to mark a guess and move on. Teach a two-pass strategy - answer everything you know, put a light mark on unsure items, then use remaining time to revisit them - and practise bubbling answers so the mechanics are automatic and do not consume thinking time.