Pre-production Testing Research Articles

Testing toxic substances for protection of the environment

The Toxic Substances Control Act requires pre-production testing of chemicals for potential hazards to human and environmental health. Effective control of chemicals requires evaluations of chemical hazard that go beyond determinations of toxicity to humans to include the effects, transport, and fate of chemicals in the environment. Formulation of meaningful hazard evaluations depends on integrating information from tests of chemical effects, transport, and fate or by developing testing tools that integrate these factors during experimentation. Chemical effects may be acute or chronic and they may be observed in individual organisms, populations of organisms, or in total ecosystems. Chemical transport through the environment depends on physico-chemical characteristics of the chemical and the medium (soil, water, or air) as well as environmental factors and biotic processes. The ultimate fate of chemicals (persistence, transformation, or degradation) is determined by numerous physical and biological processes occurring in the environment, and must be acknowledged to effectively determine the hazard. Many techniques are available for the separate and routine evaluation of the effects, transport and fate of environmental contaminants. However, separate identification of the importance and magnitude of each of these factors limits their utility in assessments of chemical hazard. The microcosm (model ecosystem) method integrates many of these tests in replicable experimental units, and may provide substantial information on chemical hazard in ecosystem context.

A Shorter Truncated Sequential Test

This paper develops a truncated sequential test (TST) for production models that makes use of the preproduction testing and that allows unequal sample sizes from the production and the preproduction models. An example is given that compares the fixed time test (FTT) against the proposed truncated sequential test. In this example a significant reduction in testing required on the production model is achieved. Power tables for such tests are tabulated.

Theory and application of preproduction testing

A showing, to a small audience, before production has begun, may be useful to give a film maker advance information about the reactions of an audience to his film. Such tests are most useful when used early in the process of production, but not before the material available for showing to the test audience bears a systematic resemblance to the finished film. In most cases, the story board is the earliest stage at which a film may be tested, although exceptions are found to this rule. Testing cannot be utilized unless the producer's intent and the target audience are specified, and is most apt to be profitable when the content is very complex or when the production unit has had no experience with a topic or technique. Useful information may be obtained by any alert producer, but if the target audience is heterogeneous or has not been clearly specified, or if precise and careful predictions are needed, the services of poll and survey specialists or a phsychological test constructor should be sought.