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WELCOME

WELCOME. INTRODUCTION TO STATISTICAL VALIDATION. JIJO PAUL K. APPROACHES TO VALIDATION. Statistical or Retrospective Validation – Based on historical data . Experimental Validation – Based on plant trials data. STATISTICAL VALIDATION.

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WELCOME

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  1. WELCOME

  2. INTRODUCTION TO STATISTICAL VALIDATION JIJO PAUL K

  3. APPROACHES TO VALIDATION • Statistical or Retrospective Validation – Based on historical data . • Experimental Validation – Based on plant trials data

  4. STATISTICAL VALIDATION • To be done before carrying out experimental validation. • Retrospective validation is an approach based on analysis of historical data. • More the no of trials better will be the statistical validation results. • The results will indicate that whether the process is under control or not.

  5. STATISTICAL TOOLS CONSIDERED FOR VALIDATION • Control charts • Capability study • Scatter diagrams

  6. STATISTICAL TERMS : • Standard Deviation – Sigma ( s ) • Mean - µ • Slope - b • Y Intercept - a • Upper Standard Limit - USL • Lower Standard Limit - LSL • Process capability index - Cp • Process performance index upper - Cp K upper • Process performance index lower - Cp K lower • Correlation Coefficient – r • Coefficient of determination - R2 • Regression line y = a + bx • Control Ratio - CR

  7. CONTROL CHARTS - APPLICATIONS • “Early Warning” • Assures that Process is Working • Provides Information on “Process Capability” • Distinguishes between common and spl cause problems +3  -3 Time

  8. CAPABILITY STUDY Capability studies are performed to evaluate the ability of a process to consistently meet a specification. Cp = (allowable range)/6s = (USL - LSL)/6s. Where Cp is the capability index. Cpk = min[ (USL - m)/3s, (m - LSL)/3s ].Where Cpk is the process performance index. CR = (UCL-LCL)/(USL-LSL). Where CR is control ratio.

  9. PROCESS CAPABILITY Good CPK>1 LSL USL Cp > 1 CR < 1 -3 +3 Poor CPK<1 USL LSL Cp < 1 CR > 1 -3 +3

  10. EXAMPLES for Control Charts

  11. Mean +/- 1S +/- 2S +/- 3S

  12. Mean +/- 1S +/- 2S +/- 3S

  13. SCATTER DIAGRAMS Scatter Diagrams are used to study and identify the possible relationship between the changes observed in two different sets of variables.

  14. SCATTER DIAGRAMS The coefficient of determination ranges from 0 to 1. An R2 of 0 means that the dependent variable cannot be predicted from the independent variable. An R2 of 1 means the dependent variable can be predicted without error from the independent variable. The quantity r, called the linear correlation coefficient, measures the strength and the direction of a linear relationship between two variables.

  15. Importance of correlation coefficient • The value of r is such that -1 <r< +1.  The + and – signs are used for positive linear correlations and negative linear correlations respectively • A correlation greater than 0.8 is generally described as strong, whereas a correlation less than 0.5 is generally described as weak.  • The coefficient of determination, r 2, is useful because it gives the proportion of the variance (fluctuation) of one variable that is predictable from the other variable.

  16. EXAMPLE for Scatter Diagramme

  17. EXPERIMENTAL VALIDATION • To be done once statistical validation is completed and found to be satisfactory. • Run full process according to SOP n times. • Record all required data in the batch process records (BPR). • Deviations to the procedures must be recorded on the data record forms. • Relevant samples to be given (as per sampling plan) to the QC and results to be recorded in the BPR. • Perform the routine tests associated with the process according to the SOP. Test results must be approved by QC.

  18. EXPERIMENTAL VALIDATION • Attach all data record forms and charts. • Perform all necessary calculations and statistical analysis (pre-determined). • Compare to acceptance criteria. • Prepare deviation report – Justification if any on acceptance and impact of process. • Prepare a process validation report including all relevant data. • The Process must meet all specifications for three consecutive runs. If failed, then validation has to be repeated. • Submit the Document to QA for review and approval.

  19. Thank you

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