I have a couple of these available to me but the only description is Bar Loss Evaluation and I have no idea what that entails. Can anyone tell me?

I have done some of these. You sit at the bar and order a drink and food. You usually have to pay with cash. The whole purpose of the shop is to watch the bartender to make sure they ring your sale through and give you correct change. Usually you have to observe your purchase and purchases of others.

What if you dont drink alcohol can you still take the shop at the bar drinking a soda?

It's usually called out in the guidelines - some shops do require it, and others don't. Some allow exceptions, like - you have to buy an alcoholic beverage (to test for compliance procedures), but you don't have to drink it if you don't want to. If it's not explained in the guidelines, you can always ask the schedulers :)

Yes, you have to order an alcoholic drink -- they will tell you what type in the guidelines. Also, you need to notice if any staff are drinking alcoholic drinks behind the bar. I did a shop where the bartender was serving all the staff as they came behind the bar, downed a shot and then went back to their post.

A major concern in bar loss is consistency and accuracy of pours. A bottle/keg should have X amount of pours in it, plus or minus a few. If this number is not matching the amount of drinks rang in there is an issue.

For beer pours, the key is avoiding excessive head. Certain styles(like stouts) are to be served with some head. Wine pours are usually free but these can be measured/carafed as needed. For liquor, some bars mandate all pours are measured. Some bars measure in a jigger only for expensive liquor. Some bars free pour virtually everything. Classy cocktail bars may measure to get precise combinations and flavors.

A trained bartender can free pour with great accuracy. Many are tested to pour out measured(like 1 or 2 oz) into a glass which is poured back into a jigger, to see how accurate they are. Another common test is to line up shot glasses and have the bartender pour a bunch in a row and check consistency. Most pour by count, the rule being .25 oz being one count. For a one ounce drink, the bartender counts to four before stopping the pour. Using this knowledge, you can also count their pour(and the shop might require this)

You will probably be asked to watch for any complimentary drinks given or taken by the staff. Bars have varying polices on this; at some places high spenders and regulars can be comped drinks now and then. Like any service industry, managers frequently can and do comp food and drink for unhappy customers and incorrect orders. At nicer cocktail bars customers can usually send back a drink they truly do not like, and at beer halls with large selections sampling beers is normal practice. Some bars allow bartenders to drink on the job if the customer buys the round as a compliment to the house, others may even allow for more, but this should be noted in the shop.

It seems they want to make sure you don't get more than you paid for.

It seems they want to make sure you don't get more than you paid for.