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Table 1 NOL-ABM variables

From: Development and verification of an agent-based model of opinion leadership

Variablea

Specifications

Global variables

Values can be accessed by all agents

Announced evidence—new evidence made known to agents, expressed as a probability

Value (1-100) based on a random normal distribution around a mean determined by the model user, visible to the agents

Credibility of the evidence announcer—probability that what the announcer says is true

Value (1-100) of the credibility of the random individual agent that announces the evidence, made visible to other agents

Agent set variables

Value determined by membership in a group

Unearned authority (UA)— authority resulting from the agent’s position

Defined by position: UA of staff nurses = 50, UA of educators = 80, UA of nurse managers = 90

Agent variables

Each agent has unique value assigned by the model program based on model user input of the mean

Prior-belief—individual agent’s level of confidence as to the probability of a given proposition

Agent belief at the beginning of process. Initial setting is random normal distribution (1–100) with model user adjusted mean. Sequential values are determined by the belief revision process.

Earned authority—authority based on a person’s performance

Random normal distribution (1–100) with model used adjusted mean

Motives—probability that an individual takes a course of action based on epistemic (truth) or pragmatic (utility) goals

Random normal distribution (1–100) with model user adjusted mean. <50 = pragmatic, ≥50 = epistemic.

Procedure-based agent variables

Values calculated based on agent procedures

Visibility—agent’s behaviors are made known to others

Prior belief combined with a threshold based on motives. Pragmatic agents have a lower prior-belief threshold for visibility

Credibility—evaluation about the probability that what the agent says is true

Weighted combination of earned and unearned authority. Weight based on visibility of agent.

Assessed evidence— agent’s evaluation of the truth value of new evidence

Absolute value of the difference between an agent’s prior belief and the announced evidence

Assessed credibility of announcer—agent compares his own perceived credibility with that of the announcer

Absolute value of the difference between an agent’s own credibility and credibility of the announcer who shares the new evidence

Uncertainty—agent unable to assess the truth value of the evidence

Based on a threshold of evidence and credibility assessments. Determines need for advice

Availability— agent meets the threshold requirements to act as an advice giver

Visible agents with a model user adjusted threshold of credibility available for giving opinion to other agents seeking advice

Get advice— seek out available agents as a resource to decrease uncertainty about evidence

Agents who need advice create links with available opinion resources (potential OLs). Reassess evidence and announcer credibility based on the beliefs and credibility of the opinion resources

In-link—incoming communication from an uncertain agent to an agent available to give advice

Number of links an available agent receives from uncertain agents

Out-link—outgoing communication from an uncertain agent

Number of links an uncertain agent sends to available agents

New belief— revised probability assessment of the evidence

Agents change their beliefs based on their prior beliefs and a threshold assessment of the evidence. Individual agent’s new belief replaces the prior belief for the next sequence (tick). If the assessment does not meet the threshold for revising belief, the new belief remains the same as the prior belief. Aggregate of individual belief revision changes the overall community context in terms of consensus belief.

  1. aDerived from Joyce [14]-[16] and Kitcher [17] as described in Anderson and Whall [13].