TWAP, VWAP and POV algorithms all fall under the category of impact driven algorithms. This means they have been designed to minimize the market impact of an order, and in other words, they aim to reduce the effect of an order on the market price of an asset. To achieve this, large orders are split into smaller child orders, which are then traded over a longer period. However, due to the increased execution time, this type of algorithm exposes the user to larger market risk, which is the risk arising from fluctuations in the market price of the assets over the execution period. That is not related to the order execution. Cost driven algorithms, on the other hand, focus on the reduction of the actual trading costs. The most prominent example is implementation shortfall algorithms. Implementation shortfall at its core measures the cost of not executing an entire trade immediately at current market prices. It essentially quantifies the slippage or the difference between the decision price when you decide to trade and the final execution price. The aim of implementation shortfall algorithms is then to execute the order whilst minimizing the implementation shortfall, which basically means striking for the right balance between market impact and speed of execution. To achieve this implementation shortfall, algorithms need to dynamically adjust their execution strategy based on real time market conditions, which makes them much more complex and leads to larger variations in design across different versions offered by algorithm providers.