Barkoe
A tidemark is the line the water leaves on a harbour wall. It shows where the tide stood and how often it came back. Harbour masters read them without thinking, and they are rarely surprised by the water.
Most managers are surprised by it constantly. A resignation lands on a Tuesday, a contractor's notice ends the same week, and two people who seemed fine turn out to have been talking to someone else since spring. Each departure feels like weather. Taken together they are a tide, and they leave marks that anyone willing to look can read.
Most management habits assume the water stays put
Look at how the usual practices are built. The annual review assumes you will still be here to be reviewed next year. The career ladder assumes you want to climb the one ladder in the building. Tenure is rewarded as if staying were the whole point, and hiring starts once someone has already resigned, so the gap is guaranteed.
None of that was foolish when people spent a decade in one job. It fits badly with a labour market in which a good analyst can freelance, take a contract in another country or join a small company that did not exist two years ago, often within a single quarter. Your own last three leavers will tell you more about this than any survey. Ask how long each stayed, who they worked for afterwards, and what they went on to do.
The cost of getting this wrong is easy to underrate because it arrives in pieces. The person who knew why the payment run fails on the last Friday of the month is gone, and nobody thought to ask before they left. The people who remain do that job badly for a quarter, then start looking themselves.
Read the marks the water leaves
A manager who wants to keep good people starts by collecting the marks. When did each person join, and when did they go? What was happening on their team in the quarter before? Which of them left within a year, and which stayed for six? Ten minutes with a spreadsheet of your own history is usually enough to show a pattern you had been putting down to bad luck.
Then sort the people you depend on into buckets, by how long you realistically expect to have them. Some you need for years, and they deserve a plan for their growth and a plan for what happens when they leave. Some you want for a season, and you should hire them that way on purpose, with a handover built in. Some you will borrow for a project, and the useful question is how quickly a stranger can pick up their work.
Each bucket calls for different management. One policy applied to all three is how you end up over-investing in people who were never staying and under-investing in the ones who might.
The people who do well in a liquid market
The people who move easily between jobs and contracts, and who are worth hiring again, show certain habits long before anyone asks for a reference. They explain their work clearly to someone who was not in the room, and they leave it in a state a stranger can pick up on a Monday morning. When they do not know something they say so, and they learn quickly once they find out.
They also keep relationships alive after a contract ends. Managers overlook this most often, because it costs nothing while the person is on your team and pays off only later, when they come back, or send a colleague, or say a good word to someone you would like to hire.
You can hire for these habits. Ask candidates to walk you through a piece of work they finished, and listen for what they handed over and how.
Why we publish this Letter
The Tidemark Letter is a small, community-driven newsletter for corporate executives, people managers and distributed workers who are thinking about how work is changing. It covers proactive work, the new labour economy and management that looks forward rather than back. It takes five minutes to read, and reading it is free.
We write some of it ourselves. The rest comes from people with something specific to say: a practice that stopped working, a bet on where the market is heading, a way of running a distributed group that others could copy.
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