An installment in a periodic series on the impact the large baby-boom generation will have on the Lehigh Valley as that population approaches retirement age.

Judy Meyers spent 20 years working in Bethlehem as an administrator for Lifepath, a nonprofit agency that assists people with developmental disabilities. Looking ahead to retirement, she began training her successor so the agency could make a seamless transition from one staffer to the next.

"She was trained for five years," said Meyers, after wrapping up one of her retirement pastimes — a low-impact aerobics class — at Allentown's YMCA earlier this week.

That's called succession planning. It's something many public and private agencies have on their minds these days as they face the so-called boomer drain — the loss of experience and institutional knowledge accompanying the departure of retiring baby boomers from the workforce.

Pennsylvania is no stranger to the demands of an older population. It has long one been of the grayer states. It is fifth on the list of states with the greatest number of residents 65 and older — roughly 1.9 million, according to the 2010 Census. Only California, Florida, New York and Texas have more.

But the sheer size of the boomer generation, which refers to the 76 million Americans born between 1946 and 1964, means pressure on what might be termed the retirement infrastructure — Social Security, health care, senior housing — will be greater than ever in coming decades, in Pennsylvania and everywhere else.

More immediately, the pressure will be on the workforce. As more and more boomers retire, the U.S. may have 4 million more jobs than workers to fill them by 2018, according to a 2012 report by the Society for Human Resource Management.

Also, the age groups filling the void may lack many of the skills required by employers. Companies will need 30 million new college-educated workers by 2020, but fewer than 23 million people will graduate from U.S. colleges in the next decade, the society said.

In the public sector, the boomer drain is known as the "silver tsunami," said Dan Egan, a spokesman for Pennsylvania's Office of Administration, which oversees the state government's workforce of nearly 73,000 and issues annual reports on its size, strength, demographic makeup and retirement numbers.

"We have tools where we can kind of project retirement trends," he said. "We have been doing that since the 1990s and it's ingrained in our practices. So we were able to see this coming."

About 32 percent of state employees will be eligible to retire in the next four years, though it's unlikely so many will. More than 80 percent of state employees are union-represented, so many may defer retirement to the later years of so-called backloaded contracts, when raises are larger and they can retire at higher pay.

State employees can retire after 25 years, but receive only a partial pension and retirement health benefits. At 35 years, they receive full pension.

Some have remained beyond retirement age to wait out periods of pay freezes during recessionary times. The Great Recession prompted many people to defer retirement. In an AARP survey in 2008, 76 percent of respondents said they planned to defer retirement because they needed the money, while 64 percent said they wanted to save more before retiring.

Pennsylvania lost 3,300 state employees to retirement in 2009-10. The following year, as the economy crawled back to life, retirements jumped to 5,100.

Egan's office assesses what succession plan needs to be in place for a given job.

"When someone retires, it's not just a reflexive 'Well, Bill retired, so we have to fill this job,' " Egan said. "We've seen changes in technology, we're seeing changes in types of employees. Are we going to need this job in the future, or can this be done in a different way?"

Not every agency has a succession procedure. East Penn School District, for example, bid goodbye to Superintendent Thomas Seidenberger on June 30 without a formal method for transferring his knowledge to his successor.

School Director Charlie Ballard said the loss to the district is tremendous. Seidenberger, who worked for 40 years in various districts, took with him 40 years of institutional knowledge.

"It means the next person [after] him will be trying to pick up all that stuff," Ballard said. "So it makes it difficult."

Ballard said he'd like to see the district institute a plan in which incoming personnel shadow more experienced workers. He plans to recommend the procedure when the new superintendent is in place.