HR Demand Forecasting Techniques: Delphi & Flow Models

When it comes to figuring out how many people an organization might need down the line, there’s no one-size-fits-all method. A lot of things come into play, and along with the usual techniques, there are a couple more that can really help: The Delphi Technique and Flow Models. Let’s break them down.

Delphi Technique

The Delphi method is a pretty unique way of estimating future staffing needs. Instead of just crunching numbers, it brings in insights from a panel of experts—usually managers or HR professionals. What makes it different is how it works in rounds.

Here’s the gist: everyone on the panel gives their thoughts or estimates separately. Then, a group of coordinators (usually HR planners) gathers all the responses, summarizes them, and shares the feedback anonymously with everyone. After that, the experts get another shot at revising their answers based on the group’s overall input. This loop goes on a few times until the group starts to agree. The final agreement becomes the official forecast.

Wechsler described the Standard Delphi Method like this:

Each round gives feedback, often in the form of stats like medians or quartiles. If someone’s opinion is way off from the rest, their reasoning might be shared too—again, anonymously—to help refine the next round of answers.

A few standout features of the Delphi method:

• It’s not a one-shot deal. It usually takes two or more rounds to get somewhere solid.
• Experts stay anonymous to avoid influence or bias.
• Feedback starts rolling in from round two, helping experts refine their opinions.
• It's especially handy for long-term planning and complex decisions.

The process kicks off by setting up a core management team, which prepares the initial set of statements or problems to be solved. These are given to the panel for review. Individual managers give their input, and once all feedback is collected, it’s given back to the experts. Eventually, the panel reaches a consensus after all ideas are considered, without the pressure of groupthink.

One of the key things in making this method work? Framing the right question. If you're forecasting HR demand, you’ll need to provide context about the current workforce situation, then let the experts weigh in.

Flow Models

Flow models are another popular go-to for forecasting how many people a company might need. The most well-known version is the Markov model—simple but effective.

Here’s how it typically works:

• Pick a time frame: Shorter time periods usually give more accurate results. But how long you forecast for depends on the organization’s bigger strategic goals.
• Create employee categories (or “states”): Everyone needs to be placed in one clearly defined category. No overlaps. You want full coverage of every possible status an employee might have (e.g., full-time, on leave, retired, transferred, etc.).
• Track employee movement (the “flow”): Over time, people move from one category to another. Some leave the company (like retirement, resignation, etc.), and some join or move around internally (transfers, promotions, etc.). These are all tracked.
• Estimate the chances of each transition: Based on past data, you figure out how likely it is for someone to move from one category to another. That helps predict what future staffing needs might look like.

Why it’s useful:

Decision-makers like it because it’s straightforward. You can explain how it works without diving into complex theory, which helps with buy-in.

The downside?

It leans a little too heavily on past data. So, if your company is going through big changes or unpredictable shifts, it might not be super accurate. It also doesn’t do great when you need to forecast for specific individuals or smaller teams.

Variations of Flow Models

If the basic Markov model doesn’t cut it, there are more advanced versions:

• Semi-Markov Model This one looks at not just the category but also how long someone’s been in that role. The logic is simple—people who've been in a position longer are more likely to move.
• Vacancy Model This method tries to predict how many openings there will be and the odds of people moving into those roles. It’s great for internal planning, especially if you're trying to prep for promotions or retirements.

The semi-Markov model helps when employees in the same role have different tenures, and you want to factor that in. The vacancy model, on the other hand, is a solid pick for mapping out the domino effect of one person leaving and others filling in gaps.

Both Delphi and flow models have their place in the HR toolkit. While Delphi taps into expert intuition for longer-term planning, flow models offer a data-backed view of how the workforce shifts over time. Together, they give a well-rounded picture for making smart, strategic staffing decisions.

Read the related article -

• HR Demand Forecasting: Methods & Techniques Explained
• Effective Techniques for Accurate HR Demand Forecasting