Carrying Capacities and Density Dependence of Firms in Organizational Populations

In developing the LV model in the previous chapter, we noted that carrying capacities are simple functions of parameters expressing density dependence in rates of birth and death. The existence of a finite carrying capacity depends on the assumption that the birth rate falls with density and that the mortality rate rises with density.

Rate Dependence and Diversity Dependence of Firms in Organizational Populations

Delacroix and Carroll (1983) argue that the founding rate for a particular kind of organization depends on the flow of recent foundings (the crude founding rate) rather than on density per se. They found that founding rates in populations of newspaper firms have cycles and that the cyclic behavior can be fitted well by

Dynamics of Selection of Firms in Organizational Populations

As we have noted in previous chapters, evolutionary selection refers to processes of differential replacement in populations. A characteristic conveys a selective advantage if it increases the likelihood that actors with the characteristic will be represented in future populations. In the biotic case, where lifetimes are reasonably tightly controlled by genes and structural characteristics

Designs of Empirical Studies in ecological perspective: Defining Events

We collected information about the life histories of all (or most) members of the organizational populations under study. In concrete terms, this means obtaining information on the timing of a series of vital events. Because organizations differ from other social actors such as individuals, a number of special issues arise in defining these vital

Designs of Empirical Studies in ecological perspective: National Labor Unions

It may seem ironic that we studied unions at a time when labor historians have largely abandoned the subject, preferring to study noninstitution- alized forms of labor action (see Gutman 1976, for example). The American labor movement has lost its momentum. In each year since 1957, the fraction of the civilian labor force affiliated

Designs of Empirical Studies in ecological perspective: Semiconductor Merchant Producers

Our second major empirical study concerns the population of firms that manufactured and sold semiconductor electronics devices in the United States between 1946 and 1984. The term “semiconductor” refers to the electrical properties of the materials from which microelectronic devices are made. Silicon is the most commonly used semiconducting material. Slices of silicon crystals

Designs of Empirical Studies in ecological perspective: Newspaper Publishers in San Francisco

The most fruitful empirical studies of organizational ecology to date have used data on populations of firms producing newspapers. Studies by Car- roll and Delacroix (1982) and Delacroix and Carroll (1983) analyzed data on such populations in Argentina and Ireland in the nineteenth and twentieth centuries. Carroll (1987) analyzed populations over similarly long periods

Designs of Empirical Studies in ecological perspective: Comparison of Data Sets

The labor union, semiconductor, and newspaper data sets cover their re- spective organizational populations over their full histories. However, the histories of unions and newspapers are a good deal longer than the 39 years for the semiconductor industry. The result is more observations over time in the union and newspaper studies. On the other

Analysis in ecological perspective: Describing Organizational Histories

An event-history (or sample-path) observation plan records information on all changes in state within some observation period. Let Y(t) denote the random variable indicating an organizations’s position at time t, and let y(t) denote a particular realization of this random variable. The set of all distinct values that Y(t) can take is called the

Analysis in ecological perspective: Models for Transition Rates

A major goal in our research is to explore the effects of population hetero- geneity on transition rates. This means analyzing how measured character- istics of organizations, populations, and environments affect rates of initiation, merger, and dissolution. 1. The Exponential Model  The baseline for comparison is the model of a constant rate: r(t) =

Analysis in ecological perspective: Counting Process Models

In developing stochastic process models of organizational foundings, the conceptual unit of analysis is obviously not the individual organization whose appearance is observed. Rather, the unit of analysis, the unit in which the foundings take place, is the population. Detailed information on foundings tells the times at which increments to the population take place.

Analysis in ecological perspective: Estimation and Testing

Our empirical analysis is done with maximum likelihood (ML) and partial likelihood (PL) estimation. This section gives a brief overview of how these two kinds of estimation strategies are used with event-history data. 1. Maximum   Likelihood The likelihood function L is defined as the joint probability (or joint proba- bility density) of sample observations.

The Population Ecology of Founding and Entry: Core Questions

In Part I we argued that rates of founding and entry in organizational populations are much more complicated than birth rates in biotic popula-tions. In particular, we proposed that organizational founding and entry rates respond to processes of competition and legitimation. According to our model, levels of competition and legitimacy vary with the number

Founding Rates of Labor Unions in the Population Ecology

Our study of national labor unions recorded 479 foundings over the 1836— 1985 period. Figure 9.1 shows how the events were distributed over time. A surge in foundings began in 1883 and continued until 1906; this was the most important period of building national unions. The peak years were 1897 and 1903, each with

Entry Rates of Semiconductor Manufacturing Firms in the Population Ecology

We next consider the same set of issues for a very different kind of organi- zational population: semiconductor manufacturing firms. Since there are many obvious technical, environmental, and operating differences between national labor unions and semiconductor companies, comparing the dynamics of the founding and entry rates in the two populations provides a strong test

Founding Rates of Newspaper Firms in the Population Ecology

Finally we consider the result of fitting the same basic models to data on founding rates of organizations that published local newspapers in the San Francisco Bay area from 1840 to 1975. This organizational form provides interesting contrasts with the two just considered. As with labor unions, records on newspaper firms go back well

The Population Ecology of Founding and Entry: Comparisons and Contrasts

Have entries into populations of labor unions, semiconductor firms, and newspaper publishers been subject to similar processes of density depen- dence? In a general sense the answer appears to be yes. For all three kinds of organizations, rates of founding depend on density. For unions and newspaper publishers the founding rates rise with increasing

Age Dependence in Failure Rates of Firms: The Liability of Newness

Stinchcombe (1965, pp. 148-150) claimed that organizations face a liability of newness: new organizations fail at higher rates than old ones. His argu- ments supporting this claim pertain to both internal organizational matters and environmental relations. New organizations are vulnerable because their participants are strangers. Efficient organization requires trust among members; and trust takes

Age Dependence in Failure Rates of Firms: National Labor Unions

We analyze the questions about the liability of newness in terms of effects on the mortality rate. To begin with the simplest possible model as a baseline of comparison, assume that there is a single overall mortality process driven by a constant rate. In other words, assume that there is a single process by

Age Dependence in Failure Rates: Exits of Semiconductor Manufacturing Firms

Next we consider the lengths of “careers’’ in the semiconductor industry, the length of time between entry and exit of firms. Limitations on the data preclude an analysis with as much detail as just reported for labor unions. Entries and exits are recorded only at yearly intervals in the data we used; so observed