British Sign Language Glossaries of Curriculum Terms

BSL Environmental Science Glossary - Lincoln index definition

Definition: Lincoln Analysis is a mathematical way of working out the number of species in a population - the process involves capturing, marking and recapturing to estimate numbers.
For example establishing the number of snails in a field. First of all collect a number of snails from different parts of the field (13); mark the shells and then put the snails back in the same place. Return to the field after a period of time (two weeks) and collect more snails (this time 29). Count the number of snails that were marked the first time (there might be 3). Conduct the following calculation 13 (number originally marked) and multiply by the number collected the second time (29) Divided the sum by the number of previously marked shells (3) amongst the 29. 13 x 29 ÷ 3 = 125. This is the likely number of snails in the field, that is 125.