Developmental Checklist: What to Watch at 24–36 Months

Between 24 and 36 months a child crosses two thresholds at once: language expands rapidly and movement becomes independent. The two feed each other — a child who can walk explores more, and a child who explores more needs more words. For that reason development in this window is read not from one domain but from how the domains relate.

Three domains under observation

The Age 2 Developmental Checklist tracks development under three headings:

• Psychomotor: gross motor skills such as running, climbing and balance, and fine motor skills such as stacking, turning pages and using a spoon.
• Cognitive: object permanence, simple matching, learning by imitation, means-end reasoning.
• Language: a widening vocabulary, two-word combinations, following single-step instructions.

Each skill is marked at one of three levels: not yet, with support, independently. That three-way split matters — the distance between "not yet" and "with support" tells you where an intervention plan should start.

Why it is not administered to the child

This is not a performance test. A two-year-old will not display most of their repertoire in front of an unfamiliar adult; stranger wariness and a short attention span see to that. So the information is taken from someone who observes the child daily — a parent or a nursery teacher. What gets measured is not peak performance but the skill shown consistently.

Reading the levels

The real information is not in the total but in how each item was marked. The three levels translate as follows.

Level marked	What it means	Evidence to look for	Implication for the plan
Not yet	The skill has not been observed	No single instance in the last two weeks	Ask whether a prerequisite skill is missing; the target may lie earlier
With support	The skill exists but not independently	Performed after a verbal prompt or hand-over-hand guidance	Fastest area of progress; the support is faded gradually
Independently	The skill counts as acquired	Repeated on different days and in at least two settings	Move to a new target; monitor only for maintenance

Those last two columns are what turn a checklist into a working plan. Of two children with the same total, the one whose marks cluster at "with support" is much closer to visible progress.

What the total does and does not say

The level bands here come from proportional division of the total, not from a normative study. That distinction is critical: the level obtained does not place a child within the distribution of their peers, it only shows how much of the listed repertoire has been acquired. Where a normative comparison is actually needed, an inventory with standardisation work behind it — such as the Ankara Developmental Screening Inventory — is the appropriate instrument.

Signs that warrant a closer look

None of the following is diagnostic on its own, but each is a reason for further assessment:

• No two-word combinations by 24 months
• Inconsistent response to their own name
• Markedly limited eye contact and joint attention, such as not following a point
• Loss of words previously used — this always warrants prompt assessment
• No observable learning by imitation

The last three are grounds for autism screening; M-CHAT is widely used in this period.

How the domains shadow one another

This is the age at which developmental domains are most entangled, and a delay in one can depress scores in another without any real deficit being present.

• Language into cognition. Most cognitive items are posed verbally. A child who does not follow the instruction fails the item even when the concept is intact.
• Motor into cognition. Matching and sequencing tasks require handling objects, so a fine motor delay can hide cognitive ability.
• Temperament into everything. A cautious child shows little of their repertoire in a new setting, which is why observation should span a period rather than a single day.

The first interpretation of a low total is therefore not "developmental delay" but "which domain might be shadowing the others?"

A case: two 30-month-olds

The first child is age-appropriate in motor and cognitive areas and clearly low on language. Vocabulary is limited, but the child points, makes eye contact and steers adults towards what they want. Communicative intent is intact; the picture suggests an expressive language delay and language support is the priority.

The second child has a similar language score, but responds inconsistently to their name, shows weak joint attention and initiates communication rarely. The numbers look alike; the clinical picture does not. Here the priority is a detailed look at social communication.

Same figure, two routes. This is why a checklist result is read alongside observation notes rather than on its own.

Practical guidance for parents completing it

When a parent fills in the form, the single biggest determinant of quality is how the questions are understood. Three rules help:

1. The two-week rule. "Has this happened in the last two weeks?" produces far more consistent answers than "does he generally do this?"
2. Once is not acquired. A skill observed a single time is marked "sometimes"; the independent level requires repeatability.
3. How much help. A skill performed after a verbal reminder sits at the support level; if physical guidance is needed, it sits lower still.

Using it to track change

The most productive use of this checklist is not a one-off measurement but a repeat every three months. Because it is observation-based there is no practice effect, so it can be completed again at short intervals. The difference between two administrations shows whether support is working far earlier than a performance test would.

Next step

After 36 months, monitoring continues with the assessment picture at three and four years. For choosing instruments by age generally, see which test and when.

Frequently asked questions

Should the parent or the teacher complete it?

Either can; ideally both, separately. The gap between home and nursery shows whether the behaviour is setting-dependent.

Is it valid if the child does not attend nursery?

Yes. The items rest on skills observable in daily life rather than on a peer group. Only the social items may have fewer opportunities for observation, and that should be noted.

How is prematurity handled?

Where there is a history of preterm birth, corrected age is used. Skipping that detail can make a typically developing child look delayed.

If the result is low, when should we look again?

If support has started, three months usually offers a meaningful window for change. Where there is regression, no waiting period applies; further assessment is requested directly.

This article is for information only. The scales and tests mentioned here are screening and assessment instruments; on their own they do not establish a clinical diagnosis. Administration and interpretation belong to licensed professionals trained in the relevant instrument. Item texts, stimulus cards, and norm tables of copyrighted tests are never published on this page.