The real cost of an unfilled healthcare vacancy

Why workforce shortages affect far more than recruitment, and what healthcare organisations can do about it.

Most healthcare leaders know exactly what a recruitment fee costs. Far fewer know what a vacancy costs once it has stayed open for six months.

During my years in NHS transformation, I spent a great deal of time supporting services through operational pressure, winter planning, service redesign and workforce change. What struck me then, and still strikes me now, is that vacancies rarely stay isolated. Their impact spreads: across teams, across services, across patients, across improvement programmes, and across budgets. And often, the most significant costs never appear on a spreadsheet.

What the evidence tells us

This is not a problem unique to one country, or one moment. England’s NHS Long Term Workforce Plan warned that, without sustained action, the NHS could face a shortfall of between 260,000 and 360,000 staff by 2036/37. The same plan put as much weight on retention as on training and recruitment, because growing the workforce means little if experienced people keep leaving.

The picture is similar across systems. The King’s Fund has long described workforce as the make-or-break issue for health and care, with NHS trusts regularly reporting well over 100,000 vacancies at any one time. In Aotearoa, Health New Zealand / Te Whatu Ora's Health Workforce Plan is candid that shortages will not be resolved quickly, and that the answer lies in long-term, prioritised workforce planning rather than short-term fixes.

The costs we can measure

Most organisations can measure the obvious things: vacancy rates, agency spend, overtime costs, time to hire. These measures matter, and they belong in every board paper. But in my experience they tell only part of the story: the part that fits neatly into a column.

The costs we feel

The costs that concern me most are the ones that never reach a workforce report. A radiographer quietly picking up extra shifts, week after week. A psychologist carrying a caseload that has grown beyond what is reasonable. A service manager spending their evenings trying to arrange cover. A senior clinician postponing improvement work because today’s operational pressure always wins. A team slowly becoming exhausted from carrying the same vacancy, month after month.

None of these appear as a line item. All of them are real, and all of them compound.

Winter pressure and service resilience

This is where the transformation lens comes in. One of the biggest lessons I learned in the NHS was that winter planning was rarely just about beds: it was about people. Flu season, sickness absence, annual-leave pressure, rising admissions and diagnostic demand all land at once, and a service already operating with vacancies has far less resilience when they do.

The same vacancy can feel very different in July than it does in January. A gap that is manageable in summer can become the difference between coping and not coping when demand peaks.

When one vacancy becomes two

Here is the part that worries me most. A vacancy adds workload. Added workload wears people down. And experienced staff under sustained pressure are exactly the people most able to leave, and most costly to lose.

Why reducing locum spend starts with retention

Let me be clear about something. Throughout my NHS career I worked alongside many outstanding agency and locum professionals, and many services simply could not have operated safely without them. The challenge is not temporary staffing. The challenge is when temporary staffing quietly becomes the workforce strategy.

Agency spend, in other words, is usually a symptom rather than the underlying problem. Treating the symptom without understanding the cause rarely holds.

Looking beyond recruitment

The strongest workforce strategies I have seen rarely begin with recruitment. They begin with understanding why people stay. Recruitment is one component: alongside retention, workforce planning, succession planning, flexible working, thoughtful international recruitment, leadership development and genuine community integration.

What your workforce is already telling you

Some of the most successful workforce initiatives I saw in the NHS were not recruitment initiatives at all. They were listening initiatives. Exit interviews, stay interviews, staff-survey results, the Friends and Family Test, sickness trends and turnover data are not just reporting tools: together they tell you where a service is quietly losing its people, and why.

Final thoughts

Healthcare organisations will always need recruitment, and vacancies will always occur. The question is not whether they can be eliminated: it is how organisations respond when they arise. The services that thrive over the next decade may not be the ones that recruit the fastest. They may be the ones that create the conditions for people to build long, fulfilling, sustainable careers.

In the end, workforce planning is not about filling posts. It is about building places where people want to stay.