SDI : Your Indication of accuracy. It is the parameter which assesses distance between your average and that of the group. The lab's precision is acceptable if the SDI is between-2 and +2. SDI = (Your Mean-Group Mean) / Group SD. Remark: SDI = 0 if your lab's mean is exactly the same as the peer group mean. SDI =1 or -1 if the ratio between your mean and the peers' mean corresponds to the usual mean difference of all members of the group.
Your SD has definitely no influence on the SDI value. |