Quantification
Quantification has probably had more written about it than any other methodological aspect of zooarchaeology (O’ Connor 2000:208) because there is no consensus as to which method is the most efficient (Crabtree and Monge 1990:114). The two most common approaches include the use of NISP and MNI. These are presented in Table 1 and reflect species abundance and diversity for the 8th Century BCE occupation at Mudaybic.
NISP stands for the number of identified specimens and refers to the number of bones attributed to the assemblage in general, or to a species in specific. For example, the NISP count for the total assemblage is 2575 bones, 8 for equids and hare (Lepus sp.), etc. NISP counts are easy to calculate once all identifications have already been carried out. NISP is additive across time and space, so adding new data to an existing database is straightforward. The term Total Number of Fragments (TNF) also refers to the same bone count (O’Connor 2000:54). Considering all the destructive (taphonomic) agents to which animal bones have been exposed for centuries or millennia, it should be assumed that NISP counts reflect only the archaeological sample rather than the death sample from which the assemblage is derived (O’Connor 2000:55).
There are a few problems with using NISP. First, this approach does not account for the fact that the number of skeletal elements differs between species (Grayson 1984:21), which inflates some taxa by overestimating their count (Klein and Cruz-Uribe 1984:25). NISP introduces an additional bias because it over-represents those species with robust diagnostic bones that are more easily identifiable (Klein 1980). NISP is sensitive to fragmentation (Klein and Cruz-Uribe 1984:25); therefore, an assemblage comprised mainly of fragmentary bones will result in artificially inflated NISP for a given species, making it appear to be more abundant than it is. The method ignores the effects of differential preservation on the bones of different taxa, a process that undoubtedly skews perceptions of relative species abundance (Grayson 1984:22). Although NISP values may not be an accurate measure of absolute species abundance, they can be used to estimate relative animal use (Redding 1994:280). NISP can show the rank order of taxa, which is sufficient when the top ranked taxon comprises the vast majority of the assemblage (O’Connor 2000:57). This situation particularly applies to the Near East where ovicaprines commonly dominate most faunal assemblages. This is also true of the Iron Age Mudaybic assemblage, of which ovicaprine remains account for nearly three quarters.
MNI (minimum number of individuals) is based on the most abundant sided element. The state of epiphyseal fusion and bone portion are taken into consideration, and the count is determined for individual species. MNI counts are unaffected by fragmentation, a problem associated with NISP. There are a few inherent problems with MNI counts, though. A main drawback to the method is its unpredictable response to aggregation, that is, how archaeological contexts are defined, grouped, then excavated, to form isolated units of study (Crabtree 1990:159; Grayson 1984:29; O’Connor 2000:212-3). Therefore, a study of MNI numbers is really a study of the decisions made relating to a particular approach to aggregation (Grayson 1984:49). Also, determining MNI counts for small samples will over-represent rare or uncommon species (Dayan 1999:481), an observation that confirms Grayson’s (1981) position that MNI, and NISP for that matter, are functions of sample size. An example of this can be seen in Table 1. NISP for gazelle (Gazella sp.) remains account for less than 1 % of the assemblage, but with at least two animals present, its MNI jumps to over 6 %. An even greater jump can be seen on the data from goat bones. Definitional and arithmetic problems are also associated with using MNI, and MNI results are not additive as they are with NISP counts. Therefore, when new information is added to an existing database, the entire assemblage must be completely reexamined in order to arrive at a new MNI value (O’Connor 2000:61). This is a tedious, time-consuming procedure (Klein and Cruz-Uribe 1984:26). For these reasons, the use of MNI has not been enthusiastically endorsed by some (Gautier 1984:245; Horwitz and Tchernov 1989:144). Since both methods have their merits and problems, it is probably safe to assume that there is no single technique that can adequately measure the relative proportions of archaeological animals. Since the actual number of animals that form any faunal assemblage lies somewhere between NISP and MNI (Hesse and Wapnish 1985:114), using both measures of abundance is the best approach to overcome quantification problems (Crabtree 1990:159-60; O’Connor 2000:217).