it is the video(s) of the randomization: when the researcher gave numbers to the treatement and placebo solutions. I have received from the researcher some numbered bottles in aluminum (in fact I see the numbers on the aluminium, in principle it is the same number on the bottle inside the aluminium) and will send the bottles to experimenters based on the instructions of the researcher, but I won't know what the numbers correspond too.
For example, if one person will have 4 rats with either-treatment-or-placebo
- I say it to the researcher
- He tells me to send bottles "14 9 17 3" (for example). He has the list so he knows whether it is treatment or placebo, but I do not
If one person has great experience in rats and has demonstrated to be very careful, to identify each rat very clearly, etc, so that she will have 4 rats with treatment and 4 rats with placebo,
- I say it to the researcher
- He tells me to send bottles "12 10 1 15 5 6 18 3" (for example). Given my instructions I know that half of them are placebos (if the researchers followed the instructions correctly) but I do not know which ones.
I have given 2 extreme examples but you can imagine many intermediate (one cage treatment, one cage placebo...). Currently we are "collecting" a list of participants who have rats of various age and trying to fugure out how to best distribute treatùents or placebos to securize the ability of the experiment to detect life extension effects if they exist.
Edited by AgeVivo, 29 November 2012 - 10:46 PM.