The Search for the Optimal Rota

One of the questions our consultants are often asked is ‘How do we create the optimal rota for this area?’This article takes you through the process that we use when Creating Optimal Rotas and discusses many of the key trade-offs that occur during rota design.

Creating Optimal Rotas – What is optimal?

The concept of an ‘optimal rota’ typically stems from the desire to generate to arrange shifts in a way that creates the best match between the resources available and the demand profile. If follows the logic that having our resources working at the time when the work needs to be done, will lead to a higher level of performance

Demand Profile

A typical Police Response demand pattern looks something like the diagram below, low levels of demand overnight, peaks in the early evening and sustained increases on Friday and Saturday evenings consistent with the night-time economy.

demand profile

Calculating a Match to Demand

Applying a shift pattern allows a comparison of the resource against the demand. Here we can see that the blue line (resource) tends to be lower than the requirement throughout the day but increases during shift overlap and overnight on Saturday and Sunday evenings.


In this case the rota provides a 59% match to demand. At Process Evolution we use the Ximes software package to help create a good match to demand.

What constrains how well we can match demand?

Creating a good match to demand is important when designing shift patterns. There are however, a number of constraints that organisations face when putting together their rotas, each of which will impact the final solution:

Shift lengths: As part of employee contracts most organisations have rules in place as to the minimum and maximum length of shifts that staff can work. Generally, these stipulate that full-time shifts must be at least 7-hours in length. This is sensible as it means that staff are not having into work for very short shifts. Some organisations also limit the maximum shift length, for example, many Police Forces have moved away from 12-hour shifts due to the increased fatigue while on shift.

Start and End times: Some organisations, particularly Police Forces, have the concept of a ‘Force Start day’ at 0700 and have agreements with staff that early shifts should not begin before this time. There is also the potential for local agreements where shifts have to be completed by a specific time.

Minimum Staffing:  In many organisations that work 24/7 there is the need to provide some resiliency to deal with unanticipated demand. As such a minimum staffing level will be stipulated which must be maintained at all times.

Team Working: Academic literature around human behaviour provides evidence that employees who work as part of a functioning team achieve higher levels of motivation and performance. Generally, within the Emergency services, staff are split into either 4 or 5 team patterns with each member of the team reporting to a single supervisor. The choice of a 4 or 5 team structure has a significant bearing on the types of shifts that employees will work.

Training requirements: Many organisations have determined that there is a need to schedule in periodic training into the rotas that employees work. These hours tend to come out of the main rota and therefore limit the time available to the employee’s core task. The frequency of training days will depend on the industry and rota structure but typically range from every 5-15 weeks.

Making a Rota from Shifts

Once the shifts have been decided there are various options as to how to put together a workable rota. These considerations will not impact the match to demand but will have bearing on the work life balance of employees. It is important to recognise that there is a difference between generating a set of shifts that is ‘legal’ compared with constructing a rota that meets the needs of the organisation and staff groups.

Rest Day rules: Organisations have thoughts on a limit to the number of consecutive days that someone can work – generally this has been set at 6, but in the case of a 6 on 4 off shift pattern it tends to be 7 to account for the training day. When putting together rotas we’d generally try to avoid allocating single rest days and instead develop rotas with a block of days off

Blocking vs. Forward Rotation: This section is about how the shifts are structured.

  • Using a blocking principle staff would generally be doing the same Type shifts in a row
    • i.e. D-D-D-D-D-D,
  • Forward rotation is when shifts would change as staff progress through the block
    • i.e. E-E-D-D-L-L

There are strengths and weaknesses to each approach with the blocking principle giving a more consistent set of start times, with forward rotation generally giving lower fatigue score as there tends to be longer periods between ending one shift and the start of the next.

Anti-Social Payments: Different rota configurations may trigger different allowances, this can be important for HR and Finance to understand

Fatigue Index: Putting the shift pattern into the Health and Safety Executive calculator to understand at what points staff would experience the highest fatigue and risk.

Staff Engagement: Throughout the process of Rota design it is important to understand the wishes of staff groups as to what makes a good rota for them.

There is evidence to show that rotas that don’t take into consideration levels of fatigue or staff wishes can lead to higher levels of abstraction through increase sickness levels. As such it is important to construct rotas that meets the needs of the organisation and the individual staff members.


This article has highlighted some of the considerations that Process Evolution consultants make when considering how best to create a shift pattern for an area. For more information about the approach used, Creating Optimal Rotas or Ximes software, please email