As many studies (crops, locations, products) of choice, without any fixed liability year after year / No hiring or replacement / No Training/ No Monitoring.
Data generated through local trials (in a particular agro-climatic zone) have better reliability, as compared to recommendations based on general findings.
It may be possible to extrapolate localized efficacy data / information from one crop to another (closely related) one, between cropping situations.
The direct efficacy of a product refers to the purpose for which it has been used and / or possible negative effects on the crop, if any.
Product sustainability in the crop production system, which is targeted.
The overall efficacy of the product is determined not only by its direct effectiveness and agronomic sustainability, but also by its economic benefits to the grower.