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I. R. Bama's Blog

28 Feb 2021

The 100 Point Coin Grading Scale: Its the Mathmatical Underpinnings that Make It Great!

| I. R. Bama

Many of you read with interest and have encouraged me to pursue a CGS system that is mathematically sound. So what makes a model or grading system useful? Well, it has to have internal validity. What is that, you may ask? Its a fancy way of saying that it accurately measures what it purports to measure in a manner stable over time and multiple observations. So you get the same results over time, every time. the other construct to be considered is observational reliability. That means that you could in this case, show a coin to any grader and you will have almost perfect agreement in giving the coin a grade.

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21 Feb 2021

The British Coin Grading System: Amazing!They Have a Different Numeric Score For Every Grade!

| I. R. Bama

Welcome to another foray into the more scientific aspects of Numismatics, if you will. Today, let us turn our attention to a grading system used widely across the world that is not the Sheldon Scale. I submit for your examination the British Grading System. A grading system is only as utilitarian as it describes as accurately as possible the present state of a coin based on the degree of agreement between observers and the stability of getting the same results over randomly chosen time periods.

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07 Feb 2021

The No Cents Liberty Nickel 1883

| I. R. Bama

Some of you are aware that I bought 26.5 lbs of foreign coins in an auction in December. Its really hard to get your mind around that many coins and it was pretty heavy but manageable. On Friday Patty and I started sorting them into Western Hemisphere, Europe and 3rd world categories. I had to have a way to make sense of them instead of looking at dissimilar coins from everywhere. When I'm done with this I can sort them by country. And thee are a few countries that I did not have in my large foreign collection.

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