- Problem definition.
In the previous Blog a statistical analysis was conducted on the blog posting data of the whole team. This exercise is essential to measure the current status of the project and allows the team to monitor, control and improve the performance of the process for the rest duration of the project. Based on the previous analysis this blog’s topic will be enhancing the results of the SPC conducted on the teams’ blog posting by reducing the limitation as much as possible. This will allow the team to explore manners of improvements in this project.
- Identify the feasible alternative.
Statistical Process Control (SPC) is tool to recognize the source of variation in a process. It is a tool that used in the industry to monitor the process variation over time, and identifies the common causes for this variation.
Following the process identified in the previous blog, in order to implement SPC the following steps should be taken :
- Identifying the measurement method
- Qualifying the measurement system
- Collect the data and initiate the SPC Charting
- Reaction plan development and documentation
- Include chart to the control plan
- Calculate the control limits
- Assess the control process
- Analyze the data to identify root cause and correct
- Design and implement actions to improve process capability
- Calculate CP and CPK and compare to Benchmark
- Monitor and focus efforts on next highest priority.
For the purpose of this paper X and R charts will be used to analyze the SPC data from the team blog posting project. This is mainly done to detect any variation on the process of the blog posting development as well as controlling the process and probably improve it if required.
As illustrated previously in the week 7 blog, that there are many types of control charts that are being used in the industry. The type of charts depends on the type of the data as following:
- Variable data: measured and plotted on a continuous scale this includes time, temperature cost and figures
- Attribute data : measured on discrete events such as shipping errors and percentage of waste
As the data collected and measured for the blog posting is time the type of control chart to be used is Average X and Range R chart with sample sizes >10.
- Development of the outcome for alternative.
To develop an Outcome the same data was used as the one collected in Blog wk7 with same assumptions.
The following were taken into consideration:
- Each individual or member of the team will be considered as Subgroup
- The 6 weeks will be considered the no. of the data collected for each subgroup
- The quality measure here, will be time
For a variable data such as the described the following data were developed to produce a control chart with± 3x Deviation.
The above data was then translated to the following chart:
The above chart was the result of the analysis conducted in blog wk 7. However as shown in the chart 4 points are above the upper control limit. Also 7 points are between -2 Sigma and the lower control limit which is a clear indication that this process is out of control. 6 points can also be seen in the zone between -1 sigma and -2 sigma.
Although the location of the Central Line (Mean) sits around 0.9Hrs and meets the specification of the project, the data around the mean line illustrates high variation that could only be interpreted as the team Blog posting is out of control. Therefore to enhance this chart the limits will be adjusted to feature more realistic limits.
The following steps are taken to develop the outcome:
Step 1: create an R bar chart from the above data:
The following data are derived:
Step 2: Establishing a revised central Line and control limits lines
This step includes revising the data by removing the points that are over the upper control limits from the original data as following:
Establish the revised control limits and central line as follow:
The following data is then produced:
This is then translated to the following chart:
- Analysis of the alternatives:
The above chart establised the revised control limits and central line. The graph still illustrates some special variation which is an indication to an out of control process. This could only be interpreted as that these variations are a result of special causes that could be due to:
- measurement in-accuracy (i.e how honest is the time reported by each member to conduct the weekly blog posting),
- different methods used to produce the blog from a member to the other,
- is the blog posting process affected by external factors such as work, family issues?
- The learning curves from one individual to the other differs
- Variation in individuals capabilities
- Change in Environment. The month of the Ramadan could be a cause for it too.
- Selection of the preferred alternatives
The conclusion of the above analysis indicates that the team blog posting is an out of control process. This requires a route cause analysis to be conducted to determine the reasons behind the variations and tackle those issues. This should be conducted as team excersise as it involves all members of the program. An initial analysis of the team performance to be conducted used as basis for the team workshop to analyze where the variations are coming from.
- Performance Monitoring and the Post Evaluation of Result.
To bring the blog posting process status to “in-control” position, a continuous updating to the SPC of this project to be conducted. As well as tackling special causes for the variation that occurred in the previous weeks.
- Steven C(2013, december 3), How to create Create X and R Charts in Excel[Video file]. Retrieved on August 1, 2014 from http://www.youtube.com/watch?v=nEE4SvRd76g
- AlShaibani M July 14 2014 Process control analysis for Blog posting. Retrived on August1, 2014 from https://pmioman14.wordpress.com/
- InfinityQS (2014). What is Statistical Process Control (SPC)?. [ONLINE] Available at: http://www.infinityqs.com/resources/what-is-spc. [Last Accessed August 1, 2014].
- Edgell R (2014). Statistical Process Control Explained. [ONLINE] Available at: http://www.winspc.com/what-is-spc/statistical-process-control-explained. [Last Accessed August 1, 2014].
- Brassard M, Ritter D, (2010). Memory Jogger 2. 2nd ed. USA: GOAL/QPC.
- LSS Money Belt. (2010, December 21). SPC Simplified – Control Charts [Video file]. Retrieved from http://www.youtube.com/watch?v=RYMIcEOh5M8