Scheduling

What is scheduling?

WFM is about having the right number of people in the right places at the right times, doing the right things. Scheduling is the part of the WFM cycle where employees are assigned to shifts and tasks in such a way that the demand for staff and the supply of staff are aligned as closely as possible.

Why does scheduling matter?

In a perfect world, the supply of staff always matches the demand for staff. There would always be exactly the right number of people needed to service customers or perform tasks in a timely fashion. Schedule efficiency, also known as ‘workload fit’, is a measure of the extent to which the ‘supply’ of staff matches the ‘demand’ for staff. The goal is perfect coverage, i.e. zero under-staffing and zero over-staffing at all times.

The unfortunate fact is that unless you schedule your employees properly, you’ll be over- or under- staffed most of the time. Forecasting and staffing calculation are important, but if you don’t schedule employees to match the calculated demand, all your efforts so far are wasted.

How does scheduling work?

There are three main scheduling methods:

• Rostering: The process of creating schedules for employees without regard for the underlying staffing demand.
• Rotas: A rota is a repeating pattern of shifts, typically used to rotate working hours so that each employee is asked to work an equal number of ‘popular’ and ‘unpopular’ shifts so that opening hours are covered. For example, in a business that is open from 8am to 10pm, an employee may have a rota consisting of 8am to 4pm in week one, 11am to 7pm in week two, and 2pm to 10pm in week three, repeating from week four onwards.
• Optimized scheduling: A scheduling method that aims to consistently minimize under- and over-staffing by matching the number of scheduled employees with the number of employees required, as closely as possible. This entails selecting the optimum start times, finish times and (optionally) break times, for all employees. Optimized scheduling maximizes schedule efficiency. It enables the consistent achievement of service level goals, while also minimizing employment costs and avoiding employee stress and burnout.

Scheduling is an art, as well as a science. Only optimized scheduling unlocks the full potential of WFM, but it is easier said than done.

Optimized scheduling: the challenge

Schedule optimization is not a trivial task. Let’s look at some scenarios.

Scenario 1 (simplified)

• Scheduling 25 employees for 5 days
• 1 activity
• Possible starting times for employees: 8:00, 9:00 or 10:00
• With shifts of equal duration

That is 3²⁵ or about 847 billion possible schedules. That’s about 100 times the size of the Earth’s entire population. Or twice the number of stars in the Milky Way galaxy.

Scenario 2 (enhanced flexibility)

• Scheduling 25 employees for 5 days
• 1 activity
• Possible starting times for employees: Between 8:00 and 10:00 in 15-minute intervals
• Employees can work 4, 5, 6, 7 or 8 hours

That is 45²⁵ possible schedules, i.e. a number with 41 digits. For comparison, the number of atoms in a typical human body has 27 digits.

Scenario 3 (realistic)

• Scheduling 100 employees for 5 days
• 10 different activities (including breaks)
• Starting times for employees are at 15-minute intervals between 8:00 and 16:00
• The length of shifts varies between 4 and 8 hours in 15-minute intervals
• Each employee can perform 5 different activities per day

That is 33,126,489¹⁰⁰ possible schedules. That’s an almost unimaginably large ‘solution space’ and finding the optimum is like finding a ‘needle in a haystack’. But the challenge doesn’t end there.

Constraints

To build a viable schedule, planners need to take into consideration all the relevant constraints, including:

• The working times specified in the employment contracts of each member of staff
• Labor laws, e.g. minimum time off between shifts, maximum working hours
• Staff availability or preferences - if this is part of your employee engagement strategy Employee Engagement
• Employees must be scheduled for activities for which they have the necessary skills. Multi-skilled employees may be scheduled to perform different activities at different times; this is known as ‘block scheduling’. Alternatively, employees may be scheduled on a blended basis, as described below

Shift bidding

It is possible to allow employees to state their preferences or ‘bid’ for shifts by breaking down the process of optimized scheduling into four steps:

1. Create schedules that are aligned with demand but are not yet assigned to employees.
2. Give employees the opportunity to state their preferences within the offered shifts, or ‘bid’ for shifts
3. Allocate employees to shifts, respecting their bids as far as possible
4. Allocate the remaining shifts to employees, while respecting the constraints

The goal of shift bidding is to combine optimization with employee engagement. It does however have some downsides. It requires much more admin effort. Three-stage optimization typically results in a slightly inferior workload fit to that which one-stage optimization achieves. Employees need to be educated about how the bidding process works, to avoid the perception of lack of fairness. For example, if 10 employees bid for an attractive shift of which 5 are available, how are the ‘winners’ and ‘losers’ selected? Realistically, shift bidding is not possible without professional WFM software.

Multi-skill blended scheduling

Employees with more than one skill will naturally spend less time waiting for work that they are qualified to handle. The greater the extent of multi-skilling, the fewer employees are required to handle the workload. This effect is known as 'pooling efficiency'. To unlock the pooling efficiency of multi-skilled employees, two components are required:

1. Blended schedules, in which employees are scheduled to be present to handle any interaction for which they have the necessary skills
2. A scheduling method that generates optimized schedules, taking into account the variable workload, all the constraints, and the multi-skill pooling efficiency. This is extremely complex and requires algorithms that are only available in powerful WFM applications

Breaks, lunches, and meetings

It is good practice to schedule breaks during the working day. Letting employees choose their own break times is empowering, but it does have potential drawbacks. If every employee went on break at the same time, customer experience would be terrible.

Introducing optimized break and lunch times has a significant positive impact on workload fit, even where employees are working on fixed rosters or simple rotas. By the same token, workload fit benefits from the optimized scheduling of meetings, training sessions, and 1:1s.

Combination

In a perfect world, every employee would be fully multi-skilled and be willing to work any shift assigned to them. In the real world, staff turnover means that universal multi-skilling can never be achieved. And it’s rare to find an organization with no employees working on legacy fixed-hours contracts. The good news is that even if just a subset of your employees can be optimized, there will be a disproportionate improvement in efficiency. Employing a ‘mix and match’ of fixed shifts, rotas, and optimized scheduling is a smart and practical move.

What impact does scheduling have?

Scheduling is where most of the magic of WFM happens: It’s the part of the WFM cycle where employees are assigned to shifts and tasks so that the right number of people are in the right places at the right times, doing the right things. Scheduling is not a trivial task. The number of permutations and the complexity of the constraints mean that building optimized schedules is practically impossible without professional software. But without effective and efficient scheduling, the goals of WFM cannot be achieved.