Buying from a catalogue on invoice (direct purchasing) can be described as a strategy of blind confidence. A buyer puts confidence in a producer because the producer has a monopoly on a product, or because it is not possible to verify the quality or the level of prices, or because earlier purchases were satisfactory, or because the producer has a good reputation. There may not even be a choice of suppliers, and the nearest, most straightforward or habitual suppliers are retained without question. Relations between suppliers and buyers are very stable.

Blind confidence can obtain drugs that are acceptable in terms of quality, price and conditions of payment and delivery. However, blind confidence does not guarantee that acceptable drugs can be obtained from sources other than national producers whose quality and prices are controlled by other means. This strategy can be used for procurement from international supply agencies such as the International Dispensary Association (IDA) and the UNICEF Supply Division who one can be confident will supply quality products at low prices.

The advantage of this strategy is its flexibility, speed and low transaction costs. The drawback is that suppliers can abuse buyers who do not try to understand the market in order to make better use of it.