2. What is control chart?
It is a graph used to study how a process changes
over time.Data are plotted in time order.It has a
central line for the average,an upper line for the
upper control limit and a lower line for lower
control limit.These lines are determined from
historical data.
3. Types of control charts
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Attribute Data : This category of control
charts displays data that results from
counting the number of occurences or items
in a single category of similar items.
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Variables Data : This category of control
charts displays values resulting from the
measurment of a continuous variable.
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Examples : Elapsed time,temperature,weight
and radiation goals.
4. Historical Application
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To understand past process performance
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To remove existing sources of natural and
unnatural variability.
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To indentify any new sources of variability
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To monitor process defects.
5. General Application
Control charts can be used:-
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When controlling ongoing processes by finding
and correcting problems as they occur.
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When predicting the expected range of
outcomes from a process.
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When determining whether a process is stable
(in statistical control).
6. Application in healthcare
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General monitoring and improvement of hospital
performance.
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Monitoring of health related variables for
individual patients.
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Survelliance of infectious diseases.
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Public health surveillance.
