Biomedical subjects

C S Reichardt

Publications and source records attributed to C S Reichardt.

3 recordsLinked to original sources

PubMed1995

Effective services for homeless substance abusers.

A heterogeneous and representative sample of 323 homeless individuals in the metropolitan-Denver area with alcohol or other substance abuse problems received a comprehensive array of substance-abuse treatment services. Following treatment, these individuals showed dramatic improvement on average in their (a) levels of alcohol and drug use, (b) housing status, (c) physical and mental health, (d) employment, and (e) quality of life. Those who received more service improved more than those who received less service. These improvements are attributable, at least partly, to the treatment rather than to alternative hypotheses such as spontaneous remission. However, the rate of improvement generally slowed during the six-month follow-up period. A random half of the clients received intensive case management in addition to the other services. Case management marginally increased clients' contacts with addictions counselors, but had little effect on the level of other services received or on the tailoring of services to client needs. As a result, case management also had little, if any, effect on outcomes.

Adult↗

PubMed1987

Taking account of time lags in causal models.

Although it takes time for a cause to exert an effect, causal models often fail to allow adequately for time lags. In particular, causal models that contain cross-sectional relations (i.e., relations between values of 2 variables at the same time) are unsatisfactory because they omit the values of variables at prior times, they omit effects that variables can have on themselves, and they fail to specify the length of the causal interval that is being studied. These omissions can produce severe biases in estimates of the size of causal effects. Longitudinal models also can fail to take account of time lags properly, and this too can lead to severely biased estimates. The discussion illustrates the biases that can occur in both cross-sectional and longitudinal models, introduces the latent longitudinal approach to causal modeling, and shows how latent longitudinal models can be used to reduce bias by taking account of time lags even when data are available for only 1 point in time.

Child↗

PubMedDate not supplied

Strong quasi-experimental designs for research on the effectiveness of rehabilitation.

Medical rehabilitation needs better understanding of the effectiveness of its treatments and of patient characteristics most responsive to alternative intervention strategies. The goal of this paper is to improve understanding of research design in medical rehabilitation. More specifically, it describes two potentially rigorous but infrequently used "quasi-experimental" research designs--the regression-discontinuity design and the multiple interrupted time-series design. These are contrasted with the strongest research design--the randomized experiment--and to weaker designs, such as the nonequivalent group designs. Pre-experimental research, including qualitative, descriptive, and predictive studies, should not be confused with experimental research designs. More frequent use of randomized experimental and strong quasi-experimental designs can provide knowledge that will augment the effectiveness of rehabilitation practice.

Humans↗