• nfojo1
  • nfojo2
  • nfojo3
  • Experienced Lecturers 100+ Master's and PhD lecturers, editors and proofreaders available
  • Professional Research We help you choose credible primary and secondary sources
  • 24/7 Support Have any questions? Talk to our support team any time, day or night.
  • Unlimited Revisions Want your paper reviewed? We will help you revise it for free


Whether you’re just starting, already have a sample and research design in mind, or have your data and results in-hand, Nfojo’s statistical consulting team can provide detailed, customized reports on optimal sampling, design, methodology, and measurement, including expert commentary and recommendations on the following:

  • Sampling frame development
  • Random sampling
  • Stratified random sampling
  • Weighted samples
  • Nonprobability sampling
  • Snowball and convenience sampling
  • Purposive sampling
  • Sample validity
  • Sample reliability
  • Sampling bias
  • Non-response bias
  • Statistical power sample testing
  • Post hoc power analysis
  • Experimental research design
  • Quasi-experimental research design
  • Pre-experimental research design
  • Non-experimental research design
  • Internal validity
  • External validity
  • Statistical conclusion validity
  • Theoretical validity
  • Measurement validity
  • Measurement reliability
  • Convergent validity
  • Divergent validity
  • Inter-item validity
  • Inter-coder reliability


We provide expertise across the gamut of research designs and quantitative modeling, analytic, and measurement techniques, alongside the right PhD-level subject matter expertise in fields including finance, macroeconomics, microeconomics, psychology, business, education, law, and public policy. Our team includes not only dedicated advanced degree methodologists, but also academics and subject matter experts who can bridge the gap between statistics and real life, providing the modeling and measurement critiques that reflect both statistical and intuitive strengths and shortfalls.

Sample Size and Selection Validity: Nfojo’s team has also provided specific assistance to dozens of firms with preemptive subsample selection as well as post hoc analysis for firms mediating disputes over subsample validity. One of the issues that we see repeatedly in our statistical consulting work is the issue of minimum required sample size. For clients seeking to estimate the needed sample size for a prospective study, we conduct an a priori statistical power analysis to determine a minimum sample size, and then randomly select the sample from the target population to meet these criteria (with or without stratification).