In an effort to recapture their youth and pull children from their iPhones, parents have led a resurgence of board games. Sales of games and puzzles in the U.S. grew 27% between 2015 and last year, hitting $2.09 billion, according to NPD Group Inc., far outpacing sales growth for all toys.

The downside to all that old-fashioned family time? Tedium.

“Your kid almost gets to the end and then they draw that card that sends them aaaaall the way back down to the start,” says Ryan O’Connor, a Deerfield, N.H., father of 5- and 6-year-old daughters. “I’ve got things to do, like make them dinner.”

That’s why parents are palming cards, strategically adding pieces when the children aren’t looking and sometimes outright lying. Not without irony, some parents have used technology to make games go faster.

Data analyst Ethan Markowitz employed statistical analysis to figure out a more efficient way of hastening Chutes and Ladders after one too many mind-numbing games. “Just like a senior citizen at the bingo parlor, my son is hooked,” he wrote on his blog detailing his findings. “All we do is spin, move, spin, move until my son performs his victory dance or, if I am unlucky enough to actually win the game, he demands a rematch.”

Mr. Markowitz says there are nine ladders and 10 chutes, “which means a bias toward losing.” So he programmed a simulation of 10,000 two-player games, which showed the dreariness could last as many as 146 turns. His solution was to tape a new ladder to the board between space 47 and 72. That lowered the longest game to 110 moves.

Barry Wise, a father who set out to help preserve “the sanity of parents” with his own data analysis, suggests eliminating the longest chute, spanning square 87 to 24. Mr. Wise, the president of data analytics firm Eigenvector Research Inc., ran his own simulations of the popular games 200,000 times.

He recommends avoiding Candy Land, with its 3.4% chance of running longer than 75 moves (compared with 0.76% for Chutes and Ladders), or eliminating the rule of sending pieces backward.

Jennifer Hogan Jones, of Wichita, Kan., has argued on board-game blog Nonstop Tabletop against purposeful losing, writing that children like her daughter need to learn how to handle disappointment. “The plan is to prepare her for losing in life so 15 years from now she won’t throw a hissy fit and slam doors the first time she loses a deal at the office,” she writes.

Even Ms. Jones admits to miscounting spaces to advantage her daughter in Sorry and Chutes and Ladders so the games will end. “It’s self-preservation,” says the human-resources executive.

Dalton James Reese of Franklin, Ky., agrees there are valuable lessons children can learn from losing. He shows his 4- and 7-year-old daughters no mercy when playing Candy Land and Monopoly. “If you want to win you’ve got to do it the right way,” he says.

Cheating to win is, of course, a time-honored tradition, even among professional board gamers. The Association of British Scrabble Players this winter imposed a three-year ban on a star player following accusations he tried to switch out undesirable tiles.

Prompted by a late 2017 survey of customers, Hasbro Inc. plans this June to release a Cheaters Edition of Monopoly. About half of respondents admitted to duplicity while playing the real-estate game. “We were quite surprised it was that high,” says marketing executive Jonathan Berkowitz. The new edition will reward players who can, say, move a rival’s piece without notice or collect rent for an opponent’s property.

Purposeful losing, on the other hand, is about making bad choices. Mr. O’Connor says card games such as Uno and Go Fish are especially easy to lose. “Kids are really bad at holding the cards, so I can see what’s in their hand,” the nuclear systems operator says. “I just ask for cards they don’t have or I’ll change the color to one that helps them.”

With two daughters under 7 years old, his troubles are twofold because he has to take turns losing to each. “It’s been getting trickier—my 6-year-old has definitely caught me,” he says. “Fortunately, I can still just pretend that she didn’t see what she saw.”

Candy Land, whose multicolored cards unsparingly punish players nearing victory, stands apart as the patron saint of board-game monotony. Hasbro’s Mr. Berkowitz says the company is aware customers may stray from the official rules of the game. “We want our fans to enjoy the games however they wish,” he says.

Matthew Stanizzi’s daughter lost recently at card game Old Maid and flung herself on the couch in a crying fit. To avoid the same outcome with Candy Land, Mr. Stanizzi uses his skills as an amateur magician to give the 3-year-old every advantage.

“Magic is the art of misdirection, but kids misdirect themselves,” says the Hollis, N.H., urologist. That gives the 41-year-old time to find and plant the best cards. “She likes to cross bridges [in the game], so I make sure she gets to do that,” he says.

Some parents, like appellate attorney Melinda Ebelhar, kept their deception away from their children for years. When playing Candy Land, she used to palm the best cards and give them to her kids at opportune moments. She let her secret slip when her now-adult children were teenagers and they haven’t let her forget.

“I’d say ‘let’s just play one game before bedtime,’ but the game would go on and on, so you’d have to do something,” she says. When they were children, “I am glad they didn’t figure out their mom, a lawyer of all things, was a cheater. What kind of lesson would that be?”

Write to Greg Bensinger at greg.bensinger@wsj.com