5. Quantification and Commingling

Question 1

Why does commingling occur?

Answer 1

Mass fatality events
Mass graves
Ossuary

Question 2

What must be done for correct recovery?

Answer 2

Careful recording at scene
Careful labelling
Extensive imaging and mapping
Associations should not be presumed
Patterns can assist with re-assembly
Recovery can cause commingling

Question 3

What must be done to sort?

Answer 3

Sorting occurs after recovery
Aims = sort, identify, rearticulate
Identify commingling
Identify and remove non-human remains
Requires anatomical/osteological knowledge

Question 4

What variation can occur in these incidents?

Answer 4

Type of incident
Number of victims
Number of recovered victims
Degree of fragmentation
Site/scene characteristics
Recovery processes

Question 5

Steps of sorting

Answer 5

Sort bone from other debris
Sort human from non-human
Inventory bones by type or side
Examine morphology
Determine age/sex/ancestry
Consider consistencies in size/length/robusticity/rugosity/joint surface congruence
Consider other info - colour/surface preservation/density/fragment fit

Question 6

Methods of reassociation

Answer 6

Visual pair matching
Articulation
Process of elimination
Osteometric comparison
Taphonomy
DNA

Question 7

Visual pair matching

Answer 7

Sort bones by element type, size and size

Sort by age

Question 8

Articulation

Answer 8

Bones form a congruent joint or juncture with another bone

Poor articulation can be basis for segregating remains

Question 9

Osteometric comparison

Answer 9

Uses statistical models to objectively compare size and shape relationships between elements
Removes subjective judgement

Extensive cortical erosion/fragmentation can cause problems
Better at exclusion than association

Question 10

How to calculate minimum number of individuals?

Answer 10

Max number of left bones plus max number of right bones minus pairs

Question 11

How to calculate most likely number of individuals?

Answer 11

(number of left plus one)x(number of right plus one)
divided by number of pairs plus 1
minus 1

Question 12

Unacceptable practices in casework

Answer 12

Uncritical combining of elements in the field based on proximity alone
Not preserving contextual information when sorting remains
Assuming that MNI estimates represent the actual number of individuals
Naive utilisation of DNA profile data
Failure to consult with specialists
Failure to document the sorting process
Using unscientific procedures to sort commingled remains