The retention picture is incomplete. Attrition data only measures one side; return rate reveals value that dropout rate alone misses.
Three measures worth tracking. Return rate, referrals from former employees, and internal mobility, alongside attrition.
The conversation with finance. Shift from “is training expensive?” to “what value does engineering development create over time?”
Mike Clarke has spent more than thirty years building engineering programmes for financial services organisations. One question keeps coming up when companies consider investing in graduate engineers: “What if we train them and they leave?”
There is another outcome worth measuring: how many come back?
Many engineering organisations track how many engineers leave. Fewer track how many return later.
These numbers tell different stories.
Dropout rate helps organisations understand short-term retention. Return rate can reveal something that attrition figures alone miss: whether former engineers choose to work with the organisation again after gaining experience elsewhere.
It can also help leaders understand the longer-term value of the relationships they build with people early in their careers.
Return rate is harder to measure, but it can add useful context to the conversation about engineering training ROI.
Engineers who receive meaningful development early in their careers may remember the organisations that gave them that opportunity.
They might leave to experience a different technology stack, work with another engineering team or take on responsibilities that were not available in their first role. Some may later decide that their original employer offers an opportunity worth returning to.
When they do return, they can bring experience and perspectives gained elsewhere.
Mike Clarke has seen the importance of early-career development across more than thirty years of building engineering programmes for financial services organisations. His experience points to a useful question for employers: what happens to the relationships they build with engineers after those people move on?
Former employees may return, recommend the organisation to other engineers or remain positive advocates for the development they received. These outcomes are worth examining alongside the more familiar measures of retention and attrition.
They should be measured rather than assumed.
The finance team’s question is reasonable. Engineering training requires time and money, and employees may leave after receiving that investment.
The challenge is understanding the full picture of the costs and benefits.
When development is limited, engineers may have fewer opportunities to progress. New hires may need more time to understand the organisation’s systems and practices. Senior engineers may also spend significant time explaining existing architecture, conventions and decisions to colleagues who are still learning the environment.
These costs can be harder to see than a training budget because they are distributed across teams and projects.
Development opportunities are one factor that may influence whether engineers stay, leave, or consider returning later. They are not the only factor, but they deserve a place in the retention conversation.
The practical question for finance is how to assess training alongside the other costs involved in building and retaining engineering capability.
Most engineering onboarding, however it is structured, has two states: training and real work. A graduate goes thrL&D and engineering leaders can start by looking at three measures alongside their existing retention data.
Return rate
Of the engineers who left during a defined period, how many have since returned?
Choose a consistent time window and compare results by cohort, role and length of service. Record how many former employees were eligible to return, where that information is available, so the figures have context.
A return rate will not tell the whole story, but it can show whether former employees continue to see the organisation as a place where they want to work.
Advocacy and referrals
How many candidates have been referred by former engineers?
Referrals from former employees can provide a useful signal about their experience of the organisation. They do not prove that training caused a positive relationship, but they can help leaders understand how former employees talk about working there.
Where possible, ask candidates how they heard about the opportunity and track referrals over time.
Internal mobility
How many engineers move into different roles or teams within the organisation?
Internal mobility helps show whether people have opportunities to develop their skills and take on new responsibilities without changing employers. Track internal moves alongside external departures to understand how engineers progress through the business.
Together, these measures provide a broader view of engineering careers than attrition figures alone.
The question is not simply whether to invest in engineering development. It is how to understand the value that investment creates over time.
Dropout rate remains important. Combine it with return rate, referrals and internal mobility, and leaders can ask more informed questions about the experience they offer engineers and the outcomes that follow.
Start with the data you already have. Ask finance and engineering leadership to review attrition alongside internal moves and returning employees. Identify where information is missing, agree on consistent definitions and establish a baseline before drawing conclusions.
That gives the organisation a practical starting point for a more complete conversation about engineering training ROI.
Start by defining what the training is intended to improve. Depending on the programme, useful measures may include time taken to contribute to real projects, technical assessment results, internal mobility, retention and feedback from engineering managers. Return rate can add a longer-term perspective where former employees can be tracked reliably. Compare results against a baseline and be careful to distinguish correlation from causation.
Track how many former engineers return over a consistent period and, where possible, compare their responsibilities and experience before leaving and after returning. Ask what skills or perspectives they gained elsewhere and whether they bring referrals. These measures can help reveal the value of maintaining positive relationships with former employees, although the value will vary by person and organisation.
Connect the training programme to business outcomes that can be measured. These might include time to contribution, the amount of senior-engineer time spent on onboarding, internal mobility and retention. Establish a baseline, agree how outcomes will be measured and review them with finance. This makes the discussion more concrete than comparing the training budget with attrition alone.
Mallon Associates has designed practitioner-led engineering programmes for investment banks and fintechs since 1990.
If you’re reviewing how your organisation develops engineers or measures the value of that investment, Anil Aphale is a good first conversation. You can discuss your engineering development goals, the challenges your teams face and what you want your programme to achieve.
Michael Clarke is the Chief Executive Officer at Mallon Associates. With over two decades of experience, including deep technical expertise in C/C++, Java, and complex proprietary frameworks, Michael now focuses on technical leadership and scaling engineering operations for financial services firms. He is a recognised expert in developer onboarding strategy, dedicated to bridging the gap between high-level technology and sustainable business growth.