Hourly employees, especially those working part-time, tend to look
at their jobs as temporary and not as a career. This doesn't tend to
foster a sense of loyalty.
Lacking loyalty and any incentives to stay (like benefits or perks)
they tend to drift in and out of the labor force. This can be
voluntary or involuntary, or from one employer to another, usually
looking for a few cents more per hour.
Why is turnover occurring?
Turnover occurs because there are
far more hourly jobs being created than there are people to fill
them. More money, benefits, perks, better
working conditions, if someone else has it, they may
dislodge your employees.
Why it's not getting better.
Demographic trends are working against you too. Jobs are being
created, but the labor force is shrinking. The "baby-boomers" born
at the close of WWII are aging. What was a plentiful supply of
cheap labor that fueled the explosion in service industry jobs is
gone. Another demographic trend is starting families later in life,
which has resulted in what is termed the "baby-bust," and smaller
families.
Long-range population projections make it clear that the
competition for workers within a reduced labor supply will continue for
some time.