Simple SummaryRoaming dogs are a common sight in many countries; they can be undernourished and unwell and may be a risk to public health. Different ways of improving the situation are proposed and attempted in many locations. To see which work, we suggest measuring dog density by counting dogs along standard routes across locations and repeating those counts at the same time of year and day, being careful to count the same way each time. It is not necessary to estimate the total number of dogs because it is the number per km of street that determines how many dogs a resident will meet on their way to school or work, and reducing density and healthier dogs would be considered a success. Smartphone applications make it easy to stick to standard routes and record dogs of different types, so we can also track things like the percentage of females with pups and the percentage of dogs that are emaciated. We present examples of such counts demonstrating large differences in densities between countries. There are few examples of counts over several years but we present one showing a definite reduction in density in a location that has provided spay and neuter services for several years.AbstractDog population management is conducted in many countries to address the public health risks from roaming dogs and threats to their welfare. To assess its effectiveness, we need to monitor indicators from both the human and dog populations that are quick and easy to collect, precise and meaningful to intervention managers, donors and local citizens. We propose that the most appropriate indicators from the roaming dog population are population density and composition, based on counting dogs along standard routes using a standard survey protocol. Smart phone apps are used to navigate and record dogs along standard routes. Density expressed as dogs seen per km predicts the number of dogs residents will encounter as they commute to work or school and is therefore more meaningful than total population size. Composition in terms of gender, age and reproductive activity is measured alongside welfare, in terms of body and skin condition. The implementation of this method in seven locations reveals significant difference in roaming dog density between locations and reduction in density within one location subject to intervention. This method provides a resource efficient and reliable measure of roaming dog density, composition and welfare for the assessment of intervention impact.