Santanu BasuWhat & How To Look At Performance Trend

Performance Trend – Time Series

Elements of Time Series

Classical Decomposition of a Time Series – Trend, Seasonality, Cycles & Residuals

A ‘Time Series’ can be decomposed into four elements:

However, scope of this session is limited to identify & interpret variation in a ‘Time Series’, through Run Chart & Control Chart

Run Chart

A ‘Run Chart’ is a graphical display of data plotted in ‘time’ order

‘Run Chart’ is used to study observed data for trends or patterns over a specified period of time

Run Chart contd….

What is a ‘Run’?

A ‘Run’ is defined as one or more consecutive data points on the same side of median. Some data points might fall on the median line, those are ignored and not considered as runs

Run Chart contd…. Two ways to count the number of runs

• Draw a circle around each ‘Run’ & count the number of circles drawn

• Count the number of times the sequence of data points crosses the median line & add ‘1’

Run Chart contd….‘Run Chart’ Rules:At least 15 data points are needed in a ‘Run Chart’ to apply any of the ‘Run Chart’ rules

Shift Trend

Number of Runs Astronomical Point

A shift in the process is indicated by 6 or more consecutive points either all above or below median. Values on median do not add or break a shift

A trend is indicated by 5 or more consecutive data points all going up or down. Like values do not add or break a trend

If values of 2 or more successive data points are same include only one while counting.

An obviously, blatantly different value

However a normal max value of a data set is not an astronomical point

To many or to few number of runs basis the number of expected runs

Run Chart contd….Number of Runs – Test of Randomness:

Expected number of ‘Run’ depends on total number of data points not on median

Control ChartControl Chart is used to track process statistics over time & to detect the presence of special causes, if any

A process is considered to be in control if all the data points are within the bound of control limits & points do not display any non-random patters

Control Chart contd….

Top 8 indicators of an out of control process:

Control Chart contd….Top 8 indicators of an out of control process - Visuals:

CUSTOMERLOGO12 | Name | Company | Customer | May 1, 2023

Thank You

Appendix 1 – Table for expected number of ‘Runs’ Table for Expected Number of Runs: