Veterinary epidemiology: software for sampling and surveys

When conducting a descriptive or analytic study which requires sampling a subset of the population, it is of vital importance to consider the required sample size. Although this can be easily achieved when using simple random sampling, it becomes more complex in the case of more complex sampling strategies. The following pieces of software are available to assist with these calculations:

• BDFree1 (sample size calculation to estimate disease freedom, using Bayesian methodology) http://www.epi.ucdavis.edu/diagnostictests/software.html
  

Also found in Bayesfreecalc2 (part of FreeBS) http://www.epi.ucdavis.edu/diagnostictests/module02.html

• CSurvey 2.0 (Cluster surveys) http://www.ph.ucla.edu/epi/csurvey.html

• FreeCalc (Epidemiological calculator for planning and analysis of surveys to detect disease or prove freedom from disease. Calculates sample size requirements based on diagnostic test sensitivity and specificity, taking population size into account, and analyses the results of such surveys) http://www.ausvet.com.au/content.php?page=software#freecalc

• G Power (Statistical power analyses for the most common statistical tests t-tests; post hoc, a priori and compromise power analyses) http://www.psycho.uni-duesseldorf.de/abteilungen/aap/gpower3/

• Herdacc [DIRECT LINK TO PROGRAM] (Program for calculating herd (aggregate) sensitivity and specificity for a wide range of values of individual level sensitivity and specificity) http://www.vetschools.co.uk/EpiVetNet/files/herdacc.exe

• PS (Interactive program for performing power and sample size calculations. It can be used for studies with dichotomous, continuous, or survival response measures. The alternative hypothesis of interest may be specified either in terms of differing response rates, means, or survival times, or in terms of relative risks or odds ratios) http://biostat.mc.vanderbilt.edu/twiki/bin/view/Main/PowerSampleSize

• SampleXS (Sample size calculator for cross-sectional surveys using simple random, systematic, or more complex sampling strategies) http://www.brixtonhealth.com/samplexs.html

• Survey Toolbox (Suite of software programs which are designed to make planning, conducting and analysing statistically valid, efficient and practical animal health surveys easier) http://www.ausvet.com.au/content.php?page=software#st

• VPLX (Calculation of variances for complex sample designs through replication) http://www.census.gov/sdms/www/vwelcome.html

• WinEpiscope (Software for sample size estimation, evaluation of diagnostic tests, cross-tabulation of data from various types of epidemiological studies, Reed-Frost simulation models etc…) http://www.clive.ed.ac.uk/cliveCatalogueItem.asp?id=B6BC9009-C10F-4393-A22D-48F436516AC4