Process Control

Control phase comprises of a system of activities whose purpose is to maintain process performance at a level that satisfies customers’ needs and drives the on-going improvement of process performance.

Without control efforts, gains made from improvement efforts may not be sustainable, due to reasons such as:

  • Process revert to its previous state
  • Operators did not follow new SOP
  • Customers change requirements
  • Suppliers change input specifications
  • New policies and regulations in place
  • Lack of ownership and accountability
  • No real improvements in the first place, Hawthorn effect

Control Methods

The tools and techniques to control processes and sustain performance includes

  • Control charts to monitor process
  • Standard Operating Procedure
  • Institutionalization
  • Project Documentation

Standard Operating Procedure

Standard operating procedure (SOP) is a detailed and usually written set of instructions for operations to achieve uniformity in the way a function is performed. SOPs are used to ensure compliance with policies and regulations. In addition, by making sure ‘best way to work’ is consistently carried out, they will result in improvement in process performance. SOP is an important control measure because the most frequently found cause of defects is due to failure to adhere to them. The common reasons for such failure include:

  • SOP not available to people who need them
  • People not trained to use SOP
  • SOP for useful for practical use

The level of standardisation is very important. If the SOP is too ‘loose’ (too little standardization), everyone will operate in a different way. The process will not be stable, process capability cannot be predicted and defects are difficult to detect. On the other hand, if the SOP is too ‘tight’ (too much standardization), the people and the process may be bogged down by ‘red tape’, creativity and learning is stifled. The right level of standardisation requires the study, development, documentation and implementation of the best method available. Good SOPs should have be frequently reviewed and improved.

Control Dashboard

The establishment of control dashboard is one of the most important steps in the Control Phase. A common mistake here is to only measure and monitor the output measure of the process. A good control dashboard should also measure and track vital few input and process measures. This is necessary because if the performance of the process is not meeting specifications, improvement actions can be identified quickly by reviewing the performance of the input and process measures, without going through the whole improvement process all over again. The control dashboard should be made available and more importantly, visual to everyone in the process. Similar to planning for data collection, it is also good practice to plan for the control dashboard. The following table shows a simple example of a control dashboard plan.

Type of measure Measure Type of visual chart Review Frequency Review By
Output Overall cycle time Time series plot Weekly Unit Head
Output Customer satisfaction Time series plot Monthly Division Head
Process Number of errors in data entry Pareto Chart Weekly Data Entry supervisor
Process Work in progress Histogram Daily Unit Head
Input Agent cycle time to submit files Time series plot Weekly Unit Head

Response Plans

The objective of the response plan is to minimise the harm from unanticipated problems by planning and providing for immediate responses. It tells people in the process what they should do if they encounter a problem in the process in order to prevent it from affecting the customer. Responses can be to conduct a service recovery, process adjustment or product recall to counteract the problem.


  1. Clarify what problem or set of problems is covered by this response plan
  2. Focusing on that specific problem, identify
    • Damage control measures : What should people do first when they notice a problem in order to prevent it from affecting customers?
    • Process adjustments : What can be done to adjust the process to counteract the problem?
    • Assess effectiveness : How you will be able to tell if the process adjustments are effective. What will appear or disappear in the data charts, for example?
    • Continuous improvement: How what you learn about this problem can be captured and incorporated into permanent process changes so it won’t appear again
  3. Assign responsibilities for acting on each of these response measures

Project Closure and Documentation

Documentation is a necessary step to ensure that the learning gained via improvement is shared and institutionalized. Good practices in documentation include:

  • Describes the flow of the process and standard procedures for operating the process including process flowcharts and work area layouts
  • Provides appropriate information on how to accomplish an activity or a series of activities for all current and future employees
  • Increases organisational learning and can be used as training materials
  • Results in clear and consistent operating procedures leading to reduced process variation