Options for Measuring and Collecting Data

The initial steps of a lean Six Sigma transformation rely heavily upon the collection of accurate data. From this information, a full picture of an organization's function may be created. This data becomes an important stepping stone in the creation of optimized processes.

For the purpose of gathering and measuring data, a number of options exist. Which system is the best fit depends largely on the type of information required as well as the organization itself.

Measurement System Analysis

A system of measurement is only as good as its accuracy. Significant organizational decisions rest upon data gathered as part of a lean Six Sigma consulting process, so establishing the validity of measurements is a critical initial step.

Measurement System Analysis, as the name implies, qualifies the value of measurements. This is done by analyzing its accuracy, precision and stability over time. Unless a system of metrics is established to be sound, little faith can be placed in resulting statistical analysis.

Of particular interest in this process is a system's ability to provide consistent results over time, the distance between an average and true values of measurements (bias), the degree of bias over the range of use. The system must also be proven to be repeatable (same results consistently yielded) and reproducible (same results with different measurement device).

Clearly, the results of this analysis determine how and if organizational processes may be measured. Before the lean Six Sigma process moves onto any data-based decision making, Measurement System Analysis must be done.

Trend Chart

Trend or Run Charts are helpful tools to illustrate trends over a given time period. This manner of display clearly shows performance of a given process in relation to a specific target.

This basic charting system uses the common X- and Y-axis configuration to plot data. For simplified interpretation, Trend Charts should include a legend, relevant scales, reference bars and a specific time frame. Noting target values and explanations of major variations on the chart is particularly valuable information for future reference.

Statistical Process Control (SPC)

SPC is a powerful tool in the lean Six Sigma transformation. It serves to reduce process variation, thereby ensuring an increase in quality and decrease in defects.

Before this control may be implemented, however, data must be gathered and charted. A control chart based upon either variable (measurements based upon a quantifiable scale, such as weight or temperature) or attribute (number of good units produced, for example) data can then be constructed. The general consensus is that variable data provides measurements of significantly higher accuracy.

Control charting may then be used to create a plan of action based on sound data.