To replicate an experiment, you take the description of the conditions, tasks, environment, fixed independent and dependent variables, analytical method and results provided by the original experimenter in the (peer-reviewed) paper they published.
If you can show the same results, with the same statistical significance, then it's reasonable to assume that the experiment shows a valid scientific phenomenon.
If you can't then one of the two experiments got it wrong and more work is needed.
The basic problem with social experiments, that are based on the judgement, feelings, or anything else that the studied group merely says it would / would-not do, thinks, feels, or otherwise emotes is completely subjective. Asking people how sad, happy, angry something makes them feel and rating that feeling - or the difference from previous values - has no scientific merit, as none of the terms used have any hard, scientific, definition and none of the participants have had their feelings "calibrated".
It's little different from a scientist (a proper one) measuring electric voltage by sticking their tongue across two electrodes, or measuring distance by eyeballing it. The level of accuracy and standardisation the social "sciences" have at present puts them on a par with chemical research: phlogiston, fixed air (CO2) in the 17th century.
As for being able to determine which variables are being measured - or even what all the variables are in their experiments, the social scientists have yet to discover their subject's version of fire.