Table 1.

Original vs. updated Movement/Physical Development milestones

	2004 Milestones	2022 Milestones
2 months	SAME OR SIMILAR
	• Can hold head up and begins to push up when lying on tummy • Makes smoother movements with arms and legs	• Holds head up when on tummy • Moves both arms and both legs
	MOVED OR DIFFERENT
		• Opens hands briefly
4 months	SAME OR SIMILAR
	• Holds head steady, unsupported • Can hold a toy and shake it and swing at dangling toys • Brings hands to mouth • When lying on stomach, pushes up to elbows	• Holds head steady without support when you are holding her • Holds a toy when you put it in his hand • Uses her arm to swing at toys • Brings hands to mouth • Pushes up onto elbows/forearms when on tummy
	MOVED OR DIFFERENT
	• May be able to roll over from tummy to back • Pushes down on legs when feet are on a hard surface
6 months	SAME OR SIMILAR
	• Rolls over in both directions (front to back, back to front) • Begins to sit without support	• Rolls from tummy to back • Leans on hands to support himself when sitting
	MOVED OR DIFFERENT
	• When standing, supports weight on legs and might bounce • Rocks back and forth, sometimes crawling backward before moving forward	• Pushes up with straight arms when on tummy
9 months	SAME OR SIMILAR
	• Can get into sitting position • Sits without support	• Gets to a sitting position by herself • Sits without support
	MOVED OR DIFFERENT
	• Pulls to stand • Stands, holding on • Crawls	• Moves things from one hand to her other hand • Uses fingers to “rake” food towards himself
1 year	SAME OR SIMILAR
	• Pulls up to stand, walks holding on to furniture (“cruising”)	• Pulls up to stand • Walks, holding on to furniture
	MOVED OR DIFFERENT
	• May take a few steps without holding on • Gets to a sitting position without help • May stand alone	• Drinks from a cup without a lid, as you hold it • Picks things up between thumb and pointer finger, like small bits of food
15 months	SAME OR SIMILAR
	NA: No 15-month checklist in original version	NA: No 15-month checklist in original version
	MOVED OR DIFFERENT
		• Takes a few steps on his own • Uses fingers to feed herself some food
18 months	SAME OR SIMILAR
	• Walks alone • Drinks from a cup	• Walks without holding on to anyone or anything • Drinks from a cup without a lid and may spill sometimes
	MOVED OR DIFFERENT
	• Eats with a spoon • May walk up steps and run • Can help undress herself • Pulls toys while walking	• Tries to use a spoon • Climbs on and off a couch or chair without help • Scribbles • Feeds herself with her fingers
2 years	SAME OR SIMILAR
	• Kicks a ball • Begins to run • Walks up and down stairs holding on	• Kicks a ball • Runs • Walks (not climbs) up a few stairs with or without help
	MOVED OR DIFFERENT
	• Climbs onto and down from furniture without help • Stands on tiptoe • Throws ball overhand • Makes or copies straight lines and circles	• Eats with a spoon
30 months	SAME OR SIMILAR
	NA: No 30-month checklist in original version	NA: No 30-month checklist in original version
	MOVED OR DIFFERENT
		• Takes some clothes off by himself, like loose pants or an open jacket • Uses hands to twist things, like turning doorknobs or unscrewing lids • Jumps off the ground with both feet • Turns book pages, one at a time, when you read to her
3 years	SAME OR SIMILAR
	None	None
	MOVED OR DIFFERENT
	• Runs easily • Climbs well • Pedals a tricycle (3-wheel bike) • Walks up and down stairs, one foot on each step	• Uses a fork • Strings items together, like large beads or macaroni • Puts on some clothes by himself, like loose pants or a jacket
4 years	SAME OR SIMILAR
	• Catches a bounced ball most of the time • Pours, cuts with supervision, and mashes own food	• Catches a large ball most of the time • Serves himself food or pours water, with adult supervision
	MOVED OR DIFFERENT
	• Hops and stands on one foot up to 2 seconds	• Unbuttons some buttons • Holds crayon or pencil between fingers and thumb (not a fist)
5 years	SAME OR SIMILAR
	• Hops; may be able to skip	• Hops on one foot
	MOVED OR DIFFERENT
	• Uses a fork and spoon and sometimes a table knife • Stands on one foot for 10 seconds or longer • Can do a somersault • Can use the toilet on her own • Swings and climbs	• Buttons some buttons

Note. Items listed under Same or Similar are unchanged, partially changed, or reworded between versions. Items listed under Moved or Different were moved to a different age checklist (with or without changes), removed, or added. Italicized items are those that were removed or added.