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By and large, we come across situations where we favor the mean value of the outcome of a process (central tendency) to be focused around a specified targeted value with as less variation as possible (dispersion). There are situations where the variation assumes relatively higher importance than the central tendency; mostly because higher variations are more intolerable than some shifts in central tendency. Interestingly, there may be certain situations where variation or controlled variation is advantageous as well. Study of Process Potential: The process potential index Cp is used to study the variation, or spread of a process with respect to specified limits. While we study process potential, we are interested in the variation and not in the central tendency. The underlying idea is that if the process is able to maintain the variation within specified limits, it is considered to possess the required potential. The centering of mean can always be achieved by setting adjustments. Or in other words, if Cp is not satisfactory, Cpk (process capability) can never be achieved, since Cpk can never exceed Cp; it can at best equal Cp. Many examples where the variation is generally considered unfavorable to the outcome: 1. Analysis of Variance While evaluating whether there is a significant difference between means (central tendency) for multiple sets of trials as in ANOVA, the variation between sets and within sets are compared using F tests. Thus in such situations, the variation comparison assumes high importance. 2. Relative grading systems For many competitive examinations, the concept of ‘percentile’ is used, which is actually a relative grading system. Here, more than the absolute mark by a student, the relative variation from the highest mark is more important, thus the relative variability becomes key decisive factor. 3. Control chart analysis While studying a process variation using a control chart, first the instability and variation are given the importance. Only if we have control on these parameters we will be able to meaningfully study the ‘Off-target’ i.e. the central tendency. 4. Temperature variation in a mold While performing certain compression molding process, temperature variation across different points on the surface of the mold does more harm than the mean temperature. Here the mean temperature is permitted to have a wider tolerance, but the variation across mold does more warping of the product. 5. Voltage fluctuations Many electrical appliances get damaged due to high variation (fluctuation) in the voltage, although the mean voltage (central tendency) is maintained. Controlled variation is favorable: 1. Load distribution in a ship While loading a ship the mean value of the load can vary, but the distribution of the load is more important to maintain the balance of the ship on water. 2. Science of music Those who understand the science of music would agree that more than the base note, the appropriate variation of the other notes with respect to the base note is extremely important to produce good music. Some examples where variation is favorable: Systematic Investment plans (SIPs) take advantage of the variation in the NAVs to accumulate wealth. Here even an adverse shift of the central tendency is compensated by the variation! Law of physics states that Force = Mass x Acceleration (F = ma). Thus, if we consider speed as the variable, it is the variation of speed that decides the force and the mean speed (central tendency) appears to have little relevance.

Checksheet It is used to systematically record and compile data from historical sources, or observations as they occur. It can be used to collect data at the location where the data is actually generated, in real time. The type of data can be quantitative or qualitative. Checksheet is one of the seven basic tools of Quality. What it does ? 1. Create an, easy to comprehend data that come from a simple efficient process 2. With every entry , creates a clean picture of facts as opposed to opinions of each team member 3. Standardizes agreement on the definition of each condition or event. How is it done? This can be deemed as a 8-step process: 1. Agree on the definition of events or conditions that are being observed Eg: If we seek root cause for Severity1 defects, then agreement to be made on “Severity1”. 2. Decide on who collects the data (decide the person who will be involved in this activity) 3. Note down the source of the data. Data could be from a sample or an entire population and it can be quantitative or qualitative. 4. Decide on the knowledge level required (for the person who is involved) to collect the data. 5. Decide on the frequency of the data collection (whether data needs to be collected on weekly, hourly, daily, monthly basis....) 6. Decide on the duration of the data collection (how long data should be collected so as to have a meaningful outcome) 7. Construct a check sheet that is simple to use, concise and complete. 8. Have consistency in accumulating the data throughout the collecting period. How can a checksheet look like A checksheet can normally have o Project Name, for which the data is collected o Person (name) who collects the data o Location in which the data is collected o Date on which the data is collected o Any significant identifiers , if applicable o A column portraying the event name o Net total for rows and columns Let us take a sample checksheet for a hospital. Project Name: In-Patient bottlenecks Name: Rajesh R Shift: Night Location : Ward Room Dates: 01-Sep-2017 to 03-Sep-2017 Reasons: Dates Total 01-Sep 02-Sep 03-Sep Patient’s Attire not taken care 1 1 1 3 Beds not available 1 1 1 3 Here ‘Shift’ is the key identifier and ‘Reason’ is the event. Let us take a sample checksheet for a Mainframe batch Project Name: Mainframe Op Name: Rajesh R Shift: Midnight Location : Batch Dates: 09-Apr-2017 to 11-Apr-2017 Reasons: Dates Total 09-Apr 10-Apr 11-Apr Weekday batch failure 1 9 1 11 Weekend batch failure 1 5 6 12 Here mainframe batch jobs fail for batch jobs running on weekdays and also for batch jobs running on the weekend. Future state of Checksheet: The checksheets have become obsolete and has been replaced by Business Process Management software. The software can handle much of complex issues with rather ease. Data can be quickly presented in a easy to view format. So the value of checksheet seems to be diminished out. From a quality perspective, personally i feel, checksheet remains to be as part of the 7 basic tools of quality. For many small companies, which still may not have the BPM software, checksheet would still the go-to-go place. Unless an organisation is well equipped with the nuances of the BPM software or any other tool (which is an alternative to Checksheet), it cannot straight-away jump into those new techniques/tools. I sincerely feel that as a result of this, Checksheet should be followed by may be in modified form by focussing on viewing format, easy at which we collect the data. Conclusion: Checksheet tool is one of the key seven tools of basic of quality tools. With it, we would be able to provide correct data to the processes.Even if it is obsolete, it can be still used by companies which cannot afford to buy advanced BPM software or tools ; or startup companies which are having staff without exposure to BPM / tools and hence they would want to experiment with checksheets to get a feel of things and then work on the tools later on. Hence Checksheet availability is still a must for people to work with.