Data Collection Methods
When collecting data, there are many methods that can be used. it is important to select the right method to ensure good and useful data is collected, as the quality of your data will directly impact the reliability of the analysis and the results of your improvement project. Commonly used data collection methods used within Lean Six Sigma projects include: Conducting surveys and Questionnaires, Observations, Interviews, collecting Machine-generated data, etc.
Surveys and Questionnaires
Surveys and questionnaires are methods of collecting both quantitative and qualitative data, depending on how you ask the question and the options given to respond, such as a 1–5 rating, which is quantitative, but an open text box to respond to a question will be qualitative.
Surveys and Questionnairs may seem a simple method of collecting data. However, it is important to consider your goals for the data to ensure you ask the right questions and provide the right options for response. Get this wrong, and you may realize after you have collected the data that you do not have any useful in your project. Another consideration is the number of questions. If you add too many questions to your survey, you are less likely to get a response. Consider surveys you have taken in the past; if they have more than 10 questions, you are less likely to complete them. According to Drive Research, the typical length of a survey is around 15 questions.
If you are going to use a survey for data collection, our advice would be to first create the survey and test it yourself, then with one or two people from your target audience, review the response, and ask for feedback if the survey made sense. You can then review the feedback and make any adjustments if necessary before sending it out to your entire data collection target audience. In most cases, you have one shot to collect the data, and a second survey being sent out will likely result in fewer responses.
Useful Free Tools for Survey Creation:
Observations
Observations are a great method of collecting data, again this method can be useful for collecting both quantitative and qualitative data. An observation usually involves going to where the process is being done, often referred to as “Going Gemba” and observing the process in real time as it is being done. This method allows for a lot of data collection of exactly what is happening in the process in reality, as opposed to what should happen which you might get from reading documents of reviewing process maps of a process.
You can observe and see how the process actually happens, conduct time-in-motion studies to see how long process steps take, and identify any issues with the process. If you are looking to collect data by observing a process, we would recommend that it is also useful to record the process as it is happening so that you can watch it back multiple times, as it is possible you could miss information that is critical to the process. It could also be used in the future as a point of reference.
However, observations are not always an ideal method of data collection, as they can be very time-consuming. Another risk is that there could be some observer bias as there is only one person collecting the data.
Interviews
Another method that can be used to collect data is through interviews. Interviews usually involve carrying out one-to-one conversations with stakeholders and are usually used to gather specific information. Interviews lend themselves to being a good method of collecting in-depth qualitative data and similar to surveys and questionnaires, you would need to prepare questions. However, as you have the person with you at the time of asking questions, you are able to adapt and ask follow-up questions to dive deeper into a specific area if necessary.
However, like observations, interviews can be incredibly time and resource-intensive. If you need to aggregate multiple responses, you are going to need to carry out multiple individual interviews. There is the option to do group interviews, but that can risk group thinking and general agreement in a group rather than individual points of view.
Documents and Records
In most modern businesses, data is stored in existing documentation, spreadsheets, records, and databases. Furthermore, with the roll-out of Industry 4.0, machines and equipment are able to generate data that can be downloaded or viewed in real-time with technology such as
PLC and SCADA or ERP software such as
SAP. This type of data is most likely going to be quantitative in nature, allowing you to understand what is going on based on numbers, which can show trends, outliers, and distributions. They are unlikely to give you in-depth knowledge of why the data is performing the way it is or if inputs were changed, for example.
We recommend that if you are going to collect data, particularly for Lean Six Sigma projects, it is a good place to start by looking at this type of data collection, as it can often be fast and give a good starting point that may direct you to conduct more in-depth data collection with observations, interviews, or surveys later on for further data collection after the initial analysis.