Michael H. MacRoberts

Problems of citation analysis: A critical review

We review the problems of citation analysis. Most of them have either not been studied or have received only cursory attention. Since major error results when these problems are not taken into account, users of citation-based literature should proceed cautiously.

Quantitative Measures of Communication in Science: A Study of the Formal Level

Studies of scientific communication have relied on citation indices and bibliographies for data. We examined papers to see how much influence appears as references in bibliographies. We found that very little does.

The Negational Reference: or the Art of Dissembling:

The Note examines the negational citation, and suggests why it is uncommon in scientific writing.

Testing the Ortega hypothesis: facts and artifacts

We examine the assumptions and data base used by researchers who have tested the Ortega hypothesis. We find that the assumptions are not supported by the data and that the data are faulty. We conclude that the results are artifactual. We recommend that any policy implemented on the basis of this research be suspended.

A Re-evaluation of Lotka's Law of Scientific Productivity

This Note examines the data base used by Lotka in propounding his Law, and by Price in elaborating it, and questions the validity of the generalizations drawn from it.

Measurement in the Face of Universal Uncertainty: A Reply to Stigler

Stephen M. Stigler is Professor of Statistics and member of the Committee on the Conceptual Foundations of Science at the University of Chicago. His recent book, The History of Statistics, examines the intellectual factors involved with the spread of statistical methods to the social sciences in the nineteenth century. Authors address: Department of Statistics, The University of Chicago, 5134 University Avenue, Chicago, Illinois 60637, USA.

Floristics of Ephemeral Ponds in East-central Texas

Abstract Beginning in 2009, we surveyed the vegetation of ephemeral ponds in Sabine and Nacogdoches counties in east-central Texas. These ponds are shallow and flat-bottomed, with a small but distinct flora dominated by grasses (Poaceae) and sedges (Cyperaceae). The floras of these ponds are most similar to those of flatwoods ponds located on the lower coastal plain. Once more common on the landscape, ponds of this type have been altered or destroyed by land-use changes and fire suppression, leading to massive encroachment of woody vegetation. The pond we sampled in Nacogdoches County has been regularly mowed for approximately 30 years to prevent woody encroachment. Currently, prescribed burning in late summer and mechanical removal of encroaching woody vegetation are being applied to better understand management options that will maintain and restore the ponds we sampled and similar sites in east-central Texas. These and other natural ponds in the West Gulf Coastal Plain have not been comprehensively studied.