Motivated by @ThatDaveCh's spreadsheet I added the daily cost of hardware (brush, razor, blade) & software (pre-shave, soap/cream) used in my shaves to the spreadsheet I use to track everything and thought it would be interesting to see if there's a relationship of those costs to how I scored each shave.
Some background on the methodology.
If you're looking for a definitive display of increased cost = increased quality the trendline should move markedly higher from left to right (i.e. positive).
Based on the total cost/shave there's a slight positive trendline but when looking at the respective hardware and software plots its clear that its the software that's providing that positive movement and the hardware is actually bringing it down slightly. Given the reasonably tight clustering and only a moderate number of outliers I'd consider the data to be credible.
This does support my anecdotal experience of the day to day shaves and how I notice a more significant difference with a more expensive soap/cream and a value brand vs. the difference between an inexpensive razor and a more expensive one.
Take it for what you will
Some background on the methodology.
- Dataset is from the start of February to the end of November so should be statistically valid with 201 entries.
- The calculation of software and blade costs is straight forward being:
Unit Price = Purchase Price ÷ Total Number of Uses From New
- For brushes and razors it's similar but with an arbitrary value of 500 used for Total Number of Uses. This could be any value if it’s consistent for each item and the Unit Price for the hardware is comparable to that of software; a large delta between the two would artificially skew the results for one category or another.
- The score is a subjective value based on my thoughts how each component (pre-shave, soap/cream, brush, razor & blade) performed for each shave plus an overall value that I would describe as my experiential rating of each shave. While I normally weight each of these based on my perceived importance of one category vs. another (i.e. in my opinion how a pre-shave performs is less important to how a blade performs so I weight the pre-shave by 0.5x and the blade by 1.25x) for the sake of this exercise everything has been weighted at 1.0x.
If you're looking for a definitive display of increased cost = increased quality the trendline should move markedly higher from left to right (i.e. positive).
Based on the total cost/shave there's a slight positive trendline but when looking at the respective hardware and software plots its clear that its the software that's providing that positive movement and the hardware is actually bringing it down slightly. Given the reasonably tight clustering and only a moderate number of outliers I'd consider the data to be credible.
This does support my anecdotal experience of the day to day shaves and how I notice a more significant difference with a more expensive soap/cream and a value brand vs. the difference between an inexpensive razor and a more expensive one.
Take it for what you will
Its all done for fun.
