Brooke Wise of Dallas says a $3.99 smartphone app called You Rule Chores has her three children, Justin, 12, Rafaela, 9, and Will, 4, actually competing to see who can do more housework. The children were involved from the start, helping their mom enter the list of chores, including laundry, cleaning up after the family dog and loading and unloading the dishwasher. Each child chose one of the app's six avatars, which include a pink kitty, a robot scientist and an intergalactic policeman.

For chores completed─and approved by Ms. Wise─the app doles out digital coins the kids can redeem for rewards, such as TV time or a trip to the yogurt store. The siblings compete to see who wins the most coins and like seeing their avatars earn new strengths and skills each time they finish a job. Rafaela says she loves playing with her kitty avatar, and 'it's fun getting paid' in rewards.

For Ms. Wise, who says she was concerned about keeping the kids busy this summer, the results have been surprising: 'They make their bed, pick up their rooms, and my daughter goes out in the yard and picks up the dog poop! I'm like, 'Who are these children?' '

While preschoolers often like to lend a hand with adult tasks, fewer parents are optimistic they will hear the words 'What can I do to help?' from their older kids. The number of 9- to 12-year-olds who help with household tasks fell 9% between 1997 and 2003 to 72%, according to the latest trend data available, published in a study in the International Journal of Time Use Research. And it may have fallen further amid kids' rising use of videogames, computers and cellphones, says the study's author, Sandra Hofferth, a family-science professor at the University of Maryland and an authority on children's time use. By ages 16 to 18, only 65% of kids take part in chores, Dr. Hofferth says.

App designer Brian Linder says he and his business partner Nathan Clark launched You Rule Chores in 2011 because 'we knew it was always a pain in the butt to get our kids to do work around the house.' They wanted to motivate kids without 'the nagging and the repeating yourself over and over until you sound like an insane person and end up doing the chores yourself,' says Mr. Linder, of Dallas, whose own sons are 9 and 12.

Parents don't mind the apps' resemblance to videogames because so many children are already entranced by games on their smartphones and hand-held game consoles, he says.

Chris Bergman of Cincinnati, father of an 18-month-old son, says he worked with another dad to launch an app called ChoreMonster earlier this year because he wanted housework to be fun for kids. 'Chores were a huge tension point in my home' when growing up, he says. 'I was always getting in trouble.' The app, available at $4.99 a month for use on the Web and with Apple's mobile devices, gives points and rewards for chores, along with passes to a Monster Carnival where kids play to win either one of the game's 200 humorous monsters or a booby prize such as stinky socks.

Hannah Carpenter of Searcy, Ark., says she had trouble structuring a housework system for her four children, ages 1 through 10, until she started using ChoreMonster in February. The app 'is a huge motivator,' and her kids are gaining skills, she says. Her 4-year-old daughter Enid has learned to fold and put away laundry, Ms. Carpenter says, and her 10-year-old daughter Tristin rushes to help out, saying, 'Don't unload the dishwasher─I want to do it.'

Other apps include Epic Win, a role-playing to-do list manager, and iRewardChart and Chore Pad, digital replacements for traditional chore charts with stickers or stars.

Chores teach kids self-control and self-regulation, says Jim Fay, co-founder of the Love and Logic Institute, a Golden, Colo., provider of parent training and resources. Research shows self-regulation─learning to invest effort and persist in finishing difficult tasks─is a powerful predictor of academic and career success. It's best to start instilling the habit early, Mr. Fay says, teaching children that chores are a shared family responsibility and each member is expected to contribute. If parents can find a way to make chores fun by, say, pretending the open washing machine is a basketball hoop, he says, 'go for it.'

Working side by side with youngsters on household jobs can be a motivator. By the time they were 3, each of Denise Benham's four kids was pushing a toy lawn mower around the yard behind their father Royce, says the Kennewick, Wash., mother. They learned as toddlers to measure and do basic math by breaking eggs for pancake batter and pouring soap into the washer. Now 4 to 16, the kids do chores with their parents most Saturdays. 'A bond is created when we work together,' Ms. Benham says, while also conveying the importance of a clean, orderly home.

Parenting experts advise treating teens like adults, setting clear expectations and consistent consequences. Jayna and David Cox write and sign a housework contract annually with their 13-year-old twins, Seth and Jenna, paying $5 a week for duties such as laundry and kitchen cleanup, says Ms. Cox, of Oklahoma City. This year, they added mowing the lawn. 'We're businesspeople, and we feel it doesn't hurt for the children to learn a few things about business,' says Ms. Cox, an information-technology project manager. The twins can earn bonuses for extra work, but their pay is docked if they slack off.

Such setups require parents to coach their kids on housework skills, but also to give up some control─and avoid micromanaging, which can lead to conflict with teens trying to assert their independence. Ms. Cox says that while she has shown Seth and Jenna how to do laundry correctly, Seth still washes colors and whites together sometimes. 'He doesn't always care if his socks were once white and are all gray now,' she says.

More important, she says, is that the twins are learning the natural consequences of failing to be responsible: 'If they don't do the laundry, they don't have clean clothes.'