Should we invest in manager development?

Should we invest in manager development?

On paper the answer is obviously yes — managers shape engagement, retention, and performance. But most people reach management by being good at something else: strong individual contributors get promoted into a role they were never trained for. One UK survey put the share of "accidental managers" — promoted without formal people-management training — at 82% of new managers (The Conversation).

So the 2026 question for HR leaders isn't whether to develop managers. It's what kind of development actually changes behavior — and whether the gap is a training problem, a selection problem, or both. This page is for HR leaders deciding how much to invest in manager development, what form it should take, and how to tell whether it worked.

Five findings from our open-licensed library, one per source, scope stated plainly.

Most managers are promoted without ever being trained to manage. The Conversation's account of "accidental managers", drawing on a CMI-commissioned YouGov survey of 4,500 UK workers and managers, reports that 82% of new managers were promoted without formal management or leadership training. The consequences it cites are concrete: only about a third of workers with an ineffective manager feel motivated, half are considering leaving within 12 months, and poor manager relationships rank among the top reasons people quit over workplace culture. The article argues organisations routinely promote technically skilled people without assessing their people-management capability — and that some competencies, like emotional intelligence, are only unevenly trainable. (Scope: UK.)

Structured, practice-based leadership training causally improves manager behavior — and the improvement lasts. The strongest causal evidence in our library is a randomized waitlist-controlled trial by Martin Grill in PLOS ONE: 49 managers and 439 employees across Swedish municipal organisations, tracked over 18 months. Managers trained with an operant, behavior-based protocol — behavior analysis, participative goal-setting, and practice with feedback — showed significantly greater improvement in their performance-feedback behavior than the control group (training-by-time interaction β = 0.30, p = 0.04), and the gains followed a continuous upward trajectory rather than fading. The lesson isn't "training works" in general — it's that behavioral, practiced training produces durable change. (Scope: Swedish municipal managers.)

At scale, line-manager training tracks with better organisational outcomes — not just happier staff. A PLOS ONE study of 7,139 firms in England (panel data, 2020–2023, controlling for sector, size, and age) found that line-manager training in mental health was significantly associated with improved staff recruitment (β = .317), retention (β = .453), customer service (β = .453), and business performance (β = .349), and with reduced long-term sickness absence from mental ill-health (β = -.132). It is the first large-scale, multi-sector, company-level evidence linking this kind of manager training to hard organisational outcomes. (Scope: England; associational, not causal.)

What good managers actually do has identifiable mechanisms you can build. A PLOS ONE study of engaging leadership by Mazzetti and Schaufeli — 1,048 employees in 90 teams at a Dutch public-service agency, two waves — found that engaging leaders raise engagement and team effectiveness through two channels: followers' psychological capital (optimism, resilience, self-efficacy) at the individual level, and team resources (performance feedback, trust, communication, participation in decisions) at the team level. Development has a target: these are the specific capabilities worth building, not generic "leadership." (Scope: Dutch public-service agency.)

Effective training can be HR-led and built around the context, not bought off the shelf. A Frontiers in Organizational Psychology study describes an HR-led wellbeing programme co-designed with employees in a South African company — HR professionals, without clinical expertise, delivering evidence-based training whose content employees themselves prioritised. The point for manager development: participatory, context-adapted design improves relevance and engagement, especially in settings under-served by imported Western curricula. (Scope: single South African company, qualitative.)

The sources broadly agree that manager development can work — but they disagree on where the real lever is.

It's a training problem. Grill's trial shows the right training causally changes manager behavior and the change endures; the 7,139-firm study shows manager training tracks with recruitment, retention, and performance; Mazzetti and Schaufeli show exactly which capabilities to build. On this reading, the gap is under-investment and bad training design, not the people.

It's also a selection problem. The Conversation's "accidental managers" framing points the other way: organisations create the gap by promoting technically strong people into management without checking whether they're suited to it — and some competencies, like emotional intelligence, are only unevenly trainable. On this reading, more training alone can't fix a system that keeps putting the wrong people in the role; the answer also includes better selection and a genuine alternative career path for strong individual contributors who don't want to manage.

The unresolved tension: train only, and you keep developing people who were mis-selected; fix selection only, and you abandon the managers already in post. The evidence supports doing both — and it is honest about its limits: only Grill's study is a controlled trial, the rest are associational, and all five are non-GCC (UK, Sweden, England, the Netherlands, South Africa).

So the live decision is three questions:

1. Is your manager development behavioral and practiced, or content-only? (The evidence for lasting change is specifically about the former.)
2. Are you also fixing selection — how people get into management — or only training them once they're there?
3. Can you point to a manager behavior that measurably changed 90 days later, or only to attendance?

Do: invest in manager development — the causal evidence supports it, with conditions. Grill's randomized trial is the cleanest signal in our library: structured, behavior-based training (analysis, goal-setting, practice with feedback) produced manager improvement that lasted 18 months. Build the capabilities the engaging-leadership research identifies — psychological capital and team resources — rather than generic "leadership content." At scale, the firm-level study suggests this kind of investment tracks with recruitment, retention, and performance, not just morale.

Don't: fund content-only training and call it development. The durable-change evidence is about practice and feedback, not a lecture or an LMS module. And don't treat the problem as only training: if you keep promoting strong individual contributors into management without assessing people-management aptitude — and without offering them a real non-management career path — you are manufacturing the "accidental managers" you then pay to fix.

Watch out: the evidence is non-GCC and mostly associational. Only one study is a controlled trial; the organisational-outcomes study shows association, not proof. Treat the direction as well-supported and the exact magnitudes as imported. The HR-led South African programme is the reminder — effective training is co-designed for its context, not lifted from a US/UK curriculum.

Three concrete actions for HR leaders this week.

1. Find your "accidental managers." List everyone who moved into a management role in the last two years with no formal people-management training. That group is both your highest engagement-and-retention risk and the clearest place to start — the research ties exactly this gap to disengagement and turnover.

2. Audit whether your manager training is practiced or just delivered. Pull your most recent manager-development spend and ask the question that predicts results: did managers practice behaviors with feedback and goals they revisited — or did they attend content once? The evidence for lasting change is specific to the former. If it was content-only, you funded the format least likely to move behavior.

3. Check your promotion gate, not just your training. Look at how your last cohort of managers was chosen. Was people-management aptitude assessed at all, or was strong individual performance the only criterion? Without a credible senior career path for technically excellent people who don't want to manage, you route them into management by default — and re-create the gap faster than training can close it.

Our library's manager-development evidence is global, not Gulf-specific — there are no GCC manager-training studies in the corpus (an honest gap). Three regional pressures still shape the decision.

Vision 2030 is a management-capability bet, not only a hiring one. Saudization and localization targets move nationals into management on an accelerated timeline — which makes the "promoted without training" gap more acute, not less. Filling management seats with nationals without developing them localises the headcount but not the capability.

High power distance changes what the training has to cover. In higher power-distance Gulf workplaces, the upward feedback, participation, and trust that the engaging-leadership research identifies as the active ingredients are harder to enact — so training that simply imports a Western syllabus often doesn't transfer. The Frontiers study's lesson — co-design training for the context — applies directly.

Selection and alternative career paths are harder where management is the only prestige track. Where a management title is the main route to status and pay, the "don't promote unsuited people" remedy needs a credible expert / individual-contributor ladder to be real — otherwise the accidental-manager pipeline keeps running.

(These GCC points are contextual interpretation, not drawn directly from the sources above.)

All five library sources below are open-licensed and open in our reader with the editorial-summary contract banner — our text summary on Peoplense, with the full text, author voice, and figures at the original publisher.

• Accidental managers: why people who are great at their job can fail when they get promoted — The Conversation, CC BY-ND (CMI / YouGov survey of 4,500 UK workers; 82% of new managers promoted without training; links untrained managers to disengagement and turnover)
• A randomized waitlist-controlled trial of operant-based leadership training — PLOS ONE, CC BY (Grill; 49 managers + 439 employees, Swedish municipalities, 18 months; behavior-based training causally improved feedback behavior, β = 0.30, and the gain was sustained)
• Line manager training in mental health and organisational outcomes — PLOS ONE, CC BY (7,139 English firms, 2020–2023; line-manager mental-health training associated with recruitment, retention, customer service, business performance, and lower long-term sickness absence)
• The impact of engaging leadership on employee engagement and team effectiveness — PLOS ONE, CC BY (Mazzetti & Schaufeli; 1,048 employees in 90 teams, Netherlands; engaging leadership works via psychological capital + team resources)
• A participatory HR-led training programme for employee wellbeing — Frontiers in Organizational Psychology, CC BY (South Africa; HR-led, employee-co-designed, context-adapted training; participatory design improves relevance and engagement)