Interlaboratory quality assurance program
First Claim
1. A procedure for evaluating statistically the performance of at least one apparatus in a pool of like apparatuses, by comparing the performance of said one apparatus with the performance of said like apparatuses, and by providing at least one comparative performance indicator of said one apparatus, said procedure comprising the steps of:
- performing at least one substantially identical opertion by each of said apparatuses in said pool;
producing, as a result of said performing operation, associated resultant data by each of said apparatuses, for each separate operation;
collecting said resultant data from said one apparatus and said like apparatuses;
calculating from said resultant data the arithmetic mean data of all of the pool apparatuses;
translating mathematically said resultant data from said one apparatus and said arithmetic mean data from said pool apparatuses into at least one performance value for each said operation; and
providing said performance value as an indicator specific to the precision of performance of said one apparatus as compared to the precision of performance of the pool apparatuses.
1 Assignment
0 Petitions
Accused Products
Abstract
An improved procedure for statistically evaluating the performance, precision and/or accuracy, of at least one analytical instrument in a pool of like or substantially like instruments by comparing the performance of the one instrument located in one laboratory with the performance of like instruments in other laboratories. The procedure includes the step of quantitatively analyzing a reference or control specimen of known constituents by each instrument in the pool and collecting the resultant data from the one instrument in the pool and of the pool instruments. The mean data from the one instrument and of the pool instruments are mathematically correlated in a series of statistical equations for computing a novel, sensitive index known as the "Instrument Performance Index" or IPI. This IPI can be tabulated and/or graphically displayed, preferably as a single point in a Cartesian coordinate system, whereby an operator can tell at a glance the performance level with respect to both precision and accuracy of the one instrument in the pool. The ultimate IPI is composed of a novel Coefficient of Variation Index (CVI), which is a valuable measure of instrument precision, and the Standard Deviation Index (SDI), which is a measure of performance accuracy. Both the CVI and SDI are derived values according to the invention and are capable of tabulation and display.
122 Citations
21 Claims
-
1. A procedure for evaluating statistically the performance of at least one apparatus in a pool of like apparatuses, by comparing the performance of said one apparatus with the performance of said like apparatuses, and by providing at least one comparative performance indicator of said one apparatus, said procedure comprising the steps of:
-
performing at least one substantially identical opertion by each of said apparatuses in said pool; producing, as a result of said performing operation, associated resultant data by each of said apparatuses, for each separate operation; collecting said resultant data from said one apparatus and said like apparatuses; calculating from said resultant data the arithmetic mean data of all of the pool apparatuses; translating mathematically said resultant data from said one apparatus and said arithmetic mean data from said pool apparatuses into at least one performance value for each said operation; and providing said performance value as an indicator specific to the precision of performance of said one apparatus as compared to the precision of performance of the pool apparatuses.
-
-
2. A procedure for evaluating statistically the performance of at least one apparatus in a pool of like apparatuses, by comparing the performance of said one apparatus with the performance of said like apparatuses, and by providing comparative performance indicators of said one apparatus, said procedure comprising the steps of:
-
performing at least one substantially identical operation by each of said apparatuses in said pool, said operation including analyzing quantitatively a reference specimen having at least one known constituent; producing, as a result of said performing operation, associated resultant data by each of said apparatuses, for each separate operation; collecting said resultant data from said one apparatus and said like apparatuses; calculating from said resultant data the arithmetic mean data of all of the pool apparatuses; translating mathematically said resultant data from said one apparatus and said arithmetic mean data from said pool apparatuses into one pair of performance values for each said operation, said pair of performance values being indicators respectively specific to the accuracy and precision of performance of said one apparatus as compared to the accuracy and precision of performance of the pool apparatuses; and displaying graphically said pair of performance values as a single point, by using them as a pair of coordinates in a Cartesian coordinate system, said single point indicating both said accuracy and precision.
-
-
3. A procedure for evaluating statistically the performance of at least one apparatus in a pool of like apparatuses, by comparing the performance of said one apparatus with the performance of said like apparatuses, and by providing at least one comparative performance indicator of said one apparatus, said procedure comprising the steps of:
-
performing at least one substantially identical operation by each of said apparatuses in said pool; producing, as a result of said performing operation, associated resultant data by each of said apparatuses, for each separate operation; collecting said resultant data from said one apparatus and said like apparatuses; calculating from said resultant data the arithmetic mean data of all of the pool apparatuses; computing mathematically from said resultant data and said arithmetic mean data the standard deviation and the coefficient of variation for said one apparatus and said pool apparatuses, and deriving therefrom at least one of (a) a Coefficient of Variation Index performance value and (b) a Coefficient of Deviation Index performance value, and providing said performance value as an indicator specific to at least one of (a) the precision of and (b) the accuracy of performance of said one apparatus as compared to at least one of said precision and said accuracy of performance of the pool apparatuses. - View Dependent Claims (4, 6, 10, 13, 14, 17, 18, 19, 21)
-
-
5. Coefficient of Variation CV=SD×
- 100/a;
7. Pool Coefficient of Variation PCV=PSD×
100/b; andPSD is the pool standard deviation, a is mean value, and b is pool mean.
- 100/a;
-
7. Coefficient of Variation ##EQU13##
- 8. Pool Coefficient of Variation PCV ##EQU14##
-
9. 9. Coefficient of Variation Index ##EQU15## and E (representative of the Greek letter Sigma) means the sum of,
x is the data values derived from the tests or operations from each apparatus in the pool, n is the number of tests, and
-
11. Standard Deviation Index SDI=a-b/MSD;
- and
-
12. E (representative of the Greek letter Sigma) means the sum of,
x is the data values derived from the tests or operations from each apparatus in the pool, n is the number of tests, and
-
16. A procedure for evaluating statistically the performance of at least one apparatus in a pool of like apparatuses, by comparing the performance of said one apparatus with the performance of said like apparatuses, and by providing at least one comparative performance indicator of said one apparatus, said procedure comprising the steps of:
-
performing at least one substantially identical operation by each of said apparatuses in said pool; producing, as a result of said performing operation, associated resultant data by each of said apparatuses, for each separate operation; collecting said resultant data from said one apparatus and said like apparatuses; calculating from said resultant data the arithmetic mean data of all of the pool apparatuses; translating mathematically said resultant data from said one apparatus and said arithmetic mean data from said pool apparatus into a pair of performance values which define coordinates, one specific to precision and the other specific to accuracy as compared to the precision and accuracy of the pool apparatuses; and displaying said pair of coordinates as a single point for visual interpretation, said single point indicating both the accuracy and precision.
-
-
20. A procedure for evaluating statistically the performance of at least one apparatus in a pool of like apparatuses, by comparing the performance of said one apparatus with the performance of said like apparatuses, and by providing at least one comparative performance indicator of said one apparatus, said procedure comprising the steps of:
-
performing at least one substantially identical operation by each of said apparatuses in said pool; producing, as a result of said performing operation, associated resultant data by each of said apparatuses, for each separate operation; collecting said resultant data from said one apparatus and said like apparatuses; calculating from said resultant data the arithmetic mean data of all of the pool apparatuses; translating mathematically said resultant data from said one apparatus and said arithmetic mean data from said pool apparatus into a pair of performance values for each said operation, one specific to precision and the other specific to accuracy, both specific to said one apparatus as compared to the precision and accuracy of the pool apparatuses, said precision performance value being defined as the Coefficient of Variation Index, and said accuracy performance value as the Standard Deviation Index.
-
Specification