Introduction of Accuracy and Precision

It is the Introduction of Accuracy and Precision

1. Accuracy and Precision Mrs. Poonam Sunil Aher  ( M.Pharm , PhD) Assistant Professor Sanjivani College of Pharmaceutical Education and Research (Autonomous),  Kopargaon , Ahmednagar-423603 (M.S.), INDIA Mobile: [phone]

2. Accuracy: Accuracy is a measure of the closeness of the experimental value to the actual amount of the substance in the matrix. The accuracy of an analytical procedure expresses the closeness of agreement between the value which is accepted either as a conventional true value or an accepted reference value and the value found. This is sometimes termed trueness. The purpose of analysis of botanicals and other natural products is quantitation of target compounds in the matrix in which the compounds occur. The most common technique for determining accuracy in natural product studies is the spike recovery method, in which the amount of a target compound is determined as a percentage of the theoretical amount present in the matrix

3. Precision: The precision of an analytical procedure expresses the closeness of agreement (degree of scatter) between a series of measurements obtained from multiple sampling of the same homogeneous sample under the prescribed conditions. Precision may be considered at three  levels: Repeatability, intermediate precision and reproducibility. Precision should be investigated using homogeneous, authentic samples. The precision of an analytical procedure is usually expressed as the variance, standard deviation or coefficient of variation of a series of measurements.

4. Repeatability Repeatability expresses the precision under the same operating conditions over a short interval of time. Repeatability is also termed intra-assay precision. Intermediate precision Intermediate precision expresses within-laboratories variations: different days, different analysts, different equipment, etc. Reproducibility Reproducibility expresses the precision between laboratories (collaborative studies, usually applied to standardization of methodology).

5. Accuracy is measure of the closeness of the experimental value to the actual or true value The precision of an analytical procedure expresses the closeness of agreement between series of measurement Here goal should be accurate Here goal should be Precise Accuracy requires closeness level in 80,100,120% or 50,100,150 % levels Precision requires repetability