Which marketing channel is most effective?

Even if a PPC ad has double the conversion to sale versus a banner ad or email campaign, it does not necessarily mean that PPC should receive the highest allocation of marketing investment. Smart advertisers have learned to track and study the contribution of each marketing channel in order to map the effectiveness and efficiency toward delivering one or several stages. The stages could apply to the AIDA model (Attention, Interest, Desire and Action) or to standard models used that chart Awareness, Consideration, Trial, Use, Useage Frequency, Loyalty.

While TV and Print are often used to build brand awareness and consideration, online marketing often impacts trial, use, frequency and loyalty. Today however, online offers plenty of opportunity to cover the full marketing spectrum from awareness to loyalty. However, to optimize efficiency and effect of marketing investments, we must be able to determine which channels are the most effective and efficient means to achieve a desired marketing objective. Here are a handful of examples of online opportunities and their strengths:
Web advertising is used often to communicate the brand's position, build consideration, raise awareness for new products and maintain top-of-mind awareness for established products. In addition it works well to encourage trial, acquire new customers as well as retain established customers and increase loyalty.
Online promotions are often used to encourage trial, stimulate word-of-mouth and improve use or purchase frequency
Search marketing is often used to encourage trial.
Email is often used to encourage trial, stimulate purchase frequency and improve customer loyalty.
All marketing channels have a synergy and contribution to one or several marketing measurement stages. (Aware - Loyalty) To begin to understand the direct effect and contribution of each marketing channel, tracking must be set up in advance to capture performance. To use brand awareness as an example, we would need to know how brand awareness will be measured, what metrics will be used in the calculation, and how much weight of importance should be assigned to each metric. Relationships with customers takes place over time. How they interact with any single campaign is just one touch point. To understand the true impact of marketing campaigns, we need to study how consumers interact with those campaigns over time.
The more competitive the marketplace, the higher the need to measure performance and the more potential marketing strategies exist to fulfill marketing objectives. In order to best navigate the opportunities, the contribution of all marketing activities to site visits and subsequent purchase behavior must be understood. The triggers to sales conversion must be identified.
An important role of a marketing strategist is to maintain a comprehensive and accurate insight into every click of every visitor, and how those relate to sales and other conversions.