The best replacement for experiment is observational study.

The best alternatives to experiment are rated as following:
★★★★★  observational study
★★★★  observation
★★★  correlation
★★★  investigation
★★  quasi experiment
★★  survey
★  correlational study
★  study
★  demonstration
★  experience
★  true experiment
★  test
★  non experiment
★  quasi-experiment
  experimentation
  trial
  case study
  control
  correlational
  lab experiment
  simulation
  quasi
  random experiment
  abu ghraib
  experimental design
  control group
  experiment
  field experiment
  stanley milgram s obedience experiment
  lab
  versuch
  research study

Your alternative for experiment is not listed? Suggest!
Speaking about experiment, one probably shouldn't forget about control group.

Other search terms related to experiment and their ratings are:
★★★★★ control group
★★★ food coloring
★★★ dry ice
★★★ independent variable
★★★ hypothesis
★★ yeast
★★ cornstarch
★★ theory
★ scientific method
★ internal validity
★ matches
mentos
You have in mind a companion for experiment and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of experiment in all years. Click on graph for more.
experiment
observational study
observation