A calculation of the theoretical significance of matched bullets

Abstract:  The comparison and identification of bullets from the striations that appear on their surfaces, after they have been fired from a gun, have been practiced since the 1920s. Although the significance of the correspondences of these impression marks has been empirically justified, there is a conspicuous absence of any theoretical foundation for the likelihood. What is presented here is the derivation of the formulae for calculating the probability for the correspondence of the impression marks on a subject bullet to a random distribution of a similar number of impression marks on a suspect bullet of the same type. The approach to the calculation entails subdividing the impression marks into a series of individual lines having widths equal to the separation distance at which a misalignment of striations between the two bullets cannot be distinguished. This distance depends upon the resolution limit imposed by the microscope as well as by the visual acuity of the examiner. A calculation of the probabilities for finding pairs and triplets of consecutively matching lines on nonmatching bullets, by an examiner with normal perception using a microscope at 40× magnification, produces values that agree well with the empirical probabilities determined by Biasotti in the 1950s and when determined for larger consecutive sequences suggest that they are extremely unlikely to occur. The formulae can be used to determine the probabilities for the random occurrence of any sequence of striae and provide a straightforward way to quantitatively justify the significance of a specific match between any two bullets.     

Political liberty and social development: An empirical investigation

Liberty is not only economic; it is political. Whether the economic system promotes social development is one question. Whether the political system promotes social development is another question. The empirical investigations indicate that for the world political liberty has a small, though significant relationship with the level of social development.By investigating groupings of alternative economic systems, it is clear that global policies to increase political liberty will not necessarily bring about desired results. In the Socialist, Mixed Socialist, and Capitalist-Statist countries political liberty appears to have virtually no relationship with social development. An increase in political liberty without an increase in economic liberty is even associated with lower levels of social development.     

“All that appears possible now is to mitigate as much as possible the trials of their closing years”1: Alfred Deakin's Attitudes to Aboriginal Affairs

This article examines Alfred Deakin's attitudes towards, and impacts upon, Aboriginal people during the period 1880–1910, drawing on newspaper articles and parliamentary debates as principal source materials. The discussion begins by charting the long, influential and often positive relationships Deakin had with several Aboriginal communities during a period as a Victorian MLA between 1881 and 1884. It then proceeds to document Deakin's extraordinary descent into paternalism and racially‐based fatalism which pervaded his later association with Aboriginal affairs whilst Victoria's Chief Secretary (1886–1890), Victorian MLA for Essendon and delegate to Federal conventions (1890–1900), as the Federation debates took shape. And finally, the article outlines the attitudes Deakin expressed towards Aboriginal people in his various post‐Federation political roles, including Attorney‐General, Prime Minister and Minister for External Affairs. In doing so, the discussion draws out the connections between Deakin's advocacy of a white Australia and his attitudes towards Aboriginal Australia, and demonstrates the extent to which the creation of a new nation both informed and responded to socio‐racial ideologies that mandated the exclusion of non‐white identities from the nation‐to‐come.     

Reagan's Welfare Reforms: Were the Program Savings Realized?

This paper provides a discussion of the impact of the Omnibus Budget Reconciliation Act of 1981 (OBRA) on AFDC caseloads and expenditures. Intervention analysis and regression analysis are used to examine whether OBRA resulted in either temporary or permanent changes in the levels of these variables. This study indicates that while OBRA may have resulted in a decline in AFDC caseloads, it did not have a significant effect on total AFDC expenditures.