Risk factors in missing persons investigations

Missing persons cases represent a significant and complex global issue, affecting thousands of families and communities each year. The phenomenon of disappearance is multifaceted, encompassing a range of scenarios from voluntary disappearances to abductions. Understanding the risk factors associated with missing persons is crucial for developing effective prevention and intervention strategies. The framework proposed by Kraemer et al. (1997) offers a systematic approach to classifying risk factors, emphasizing the importance of distinguishing between fixed markers and variable risk factors and understanding their roles in the context of missing persons. This document aims to apply Kraemer et al.’s framework to the literature on missing persons to illuminate potential risk pathways and guide future research and policy efforts.

Kraemer et al.’s Work

The work of Kraemer et al., particularly their influential 1997 paper, focuses on conceptualizing and classifying risk factors in epidemiological and psychological research. Their framework is fundamental for understanding the role of various factors in the onset or outcome of specific conditions or behaviors, including those related to health, mental health, and social issues. In the context of missing persons research, the framework provided by Kraemer et al. (1997) offers a structured approach to identifying and classifying risk factors associated with person disappearance. By applying their classification, researchers can better understand which factors are most significant and how interventions might be designed to mitigate these risks. For instance, understanding whether a risk factor is a fixed marker or a variable risk factor can guide the development of specific prevention strategies, policy formulations, and support services for those at risk of disappearing.

The meticulous distinction between types of risk factors also helps clarify the mechanisms through which certain characteristics influence the likelihood of becoming a missing person. This, in turn, sheds light on possible pathways for future research and intervention, contributing to more effective and efficient approaches to addressing the issue of missing persons.

Kraemer et al.’s work underscores the importance of a nuanced understanding of risk and its implications for research, policy, and practice, making it a fundamental reference for both scholars and practitioners.

Risk Factors: Terminology

Definition and Criteria for a Risk Factor

A measurable characteristic of each subject in a specific population that precedes the outcome of interest and is associated with an increased risk of that outcome. Example: Previous instances of running away are associated with a higher risk of future disappearances.

Distinction between Fixed Markers and Variable Risk Factors

  • Fixed Marker: A risk factor that does not change over time and cannot be modified through intervention.
    • Example: Gender and race are fixed markers as they remain constant for an individual and cannot be modified.
  • Variable Risk Factor: A risk factor that can change over time and may be influenced by interventions.
    • Example: Mental health status can vary throughout a person’s life and can be improved through therapeutic interventions.

Challenges in Establishing Causality

To establish the status of a risk factor, it is necessary to demonstrate that it precedes the outcome. This temporal precedence is crucial for distinguishing between factors that may cause the outcome and those that are merely associated with it or are a consequence of it.

Importance of Temporal Precedence

Temporal precedence is crucial for classifying a characteristic as a risk factor. Without it, researchers cannot determine whether a factor actually increases the risk of disappearance or is simply associated with it.

Risk Factors: Pathways

  • Independent Risk Factors: When two risk factors are unrelated but both are associated with the outcome, they are considered independent.
    • Example: Being female and having a history of substance abuse are independently associated with a higher risk of disappearance.
  • Overlapping Risk Factors: Risk factors that address a single construct and are related to the outcome are considered overlapping.
    • Example: Economic instability and unemployment may contribute to the broader concept of financial difficulties, which is associated with a higher risk of disappearance.
  • Indirect Risk Factors: A factor that is correlated with another risk factor but is not directly causal.
    • Example: Low educational level may be an indirect indicator of socioeconomic status, which in turn is associated with a higher risk of disappearance.
  • Mediators: A mediator explains the mechanism through which one variable affects another.
    • Example: The relationship between substance abuse and disappearance may be mediated by factors such as homelessness or mental health issues.
  • Moderators: A moderator influences the direction or strength of the relationship between two variables.
    • Example: The impact of substance abuse on the likelihood of disappearing may be moderated by gender, with different patterns observed for men and women.


Understanding the complex interaction of risk factors associated with missing persons is essential to advance research and develop effective interventions. The application of the Kraemer et al. (1997) framework in this work highlights the importance of distinguishing between different types of risk factors and their pathways. Future research should focus on longitudinal studies that can more definitively establish causality and temporal relationships, ultimately guiding more effective prevention and intervention strategies in the missing persons field.

Ferguson, L. Risk factors and missing persons: advancing an understanding of ‘risk’. Humanit Soc Sci Commun 9, 101 (2022). https://doi.org/10.1057/s41599-022-01113-8