|
In my previous articles I had discussed about Six Sigma Tools, DMAIC, and DMADV, Statistics used in Six Sigma and FMEA in the current context we are discussing about the process of Data Collection in Six Sigma. Six Sigma classifies data into two types 1. Continuous (Also called variable data), 2. Discrete (also called Attribute data)
Continuous data result from measurement on a continuous scale such as length, weight, or temperature. These scales are called Continuous because between any two values are an infinite number of other values. For example between 1.537 inches and 1.538 inches there are 1.5372, 1.5373, 1.53724 and so forth.
Discrete data results from counting the occurrence of events. Examples might include counting the number of paints run per batch of painted parts, counting the number of valves that leaked or counting the number of bubbles in a square foot of floated glass or in a software organization we can map by the number of bugs found in the software.
Continuous or variable data contain more information than discrete or attribute data. Note that variable data can be transformed into attribute data but the reverse is not true. For Example a part with a measured value of 7 inches exceeds the tolerance of 5 inches thus the part would be considered as defective however because we measured the part, we know that it is only defective but by how much so when process improvements are attempted to be implemented it may be possible to determine techniques that reduce the number of defective parts going above the tolerance level.
Collecting Data
Develop Data Collection Plans, including consideration of how the data will be collected and how it will be used. Most organizations collect large volumes of data, sometimes far more than they are able to analyse effectively. Check Sheets are often used to record the presence or absence of particular features. Some data are collected manually by having people record counts or readings check sheets or forms. In Some cases it is helpful to code data to simplify the recording process for example suppose several measurement of shaft diameters are to be recorded, the tolerance limit for the shaft diameters is set at 1.5353 to 1.5358.
Data Collection is one of the process carried out when we try to implement Six Sigma in a factory making shafts or a Software Company once the data is Collected we have to implement a measurement system for both the types of data mentioned in the Six Sigma glossary, because this exercise in the later stages allow us to improve the process or the part produced in the factory. As we had discussed about Define, Measure, Analyse, Improve & Control framework of Six Sigma data collection comes under the second stage that is measure so also statistics as we discussed earlier and FMEA comes under the third stage that is Analyse and risk mitigation comes under the fourth stage that is Improve.
For Comments and queries the Author Suresh V. Menon who has worked in various capacities as Principal Consultant, Test Manager, and Implementation Manager & ERP Consultant can be contacted at testconsultants@outlook.com
