As online marketing becomes more of a science than an art form, the value of using high quality data has never before been so crucial -- especially for those looking to justify ad spend in an increasingly cautious economy.

Getting the balance right between paid search (Search Engine Marketing) and natural search (Search Engine Optimisation) can be a delicate operation. Get it wrong, and you can waste precious marketing dollars. Get it right, and you'll reap maximum rewards in terms of conversion and sales. Keep it right, and you'll be the envy of the marketing community.

There are several common misconceptions about which tool is more effective as part of an online campaign. In this article, I'll clear those up, while offering some solutions on striking the correct balance.

The first thing to consider when looking at a search-marketing program is that there is no single 'magic bullet'. Depending on the situation, on the product, on consumer behaviour and on the campaign, there are reasons why paid might be preferable to natural search or vice versa, or why a combination of the two might always be the best bet.

But first, let's clear up the myths surrounding search marketing. The first is that you don't need paid search if you're already in the top 10 for natural search. Well, SEO is a long-term proposition. It takes time for a site's keyword optimisation and other SEO features to begin lifting a site's position on the search engines. It can also be a fickle mistress -- traffic is less reliable than with paid search.

Also, you can't control the message, timing or geographic targeting of natural search. Effectively, it is the 'word of mouth' from the 'spider'. Paid search campaigns, conversely, have immediate impact. A site launched yesterday can attract traffic today with pay-per-click (PPC) advertising. Paid search is timely and excellent for time-sensitive, high-impact campaigns and can often fill in the gaps left by SEO activity.

Turning that on its head, let's look at the second common myth that as a marketer, you don't need to bother with natural search because you can pay to get the top listings. Well, consider this: multiple research studies observing search engine user behaviour have concluded that users prefer organic listings to sponsored (PPC) listings, clicking on natural listings 70 to 80 per cent of the time. Jupiter research also found that six out of seven sales resulting from search engines originated in the organic search listings. Natural search is an excellent way of generating traffic and raising awareness, particularly near the start of the buying cycle.

So it seems obvious that a blended approach of both paid and natural search is the way to go. Anecdotally, it's true that when users see a website listed in both the organic and paid rankings, they are more likely to click through to that site, as it demonstrates credibility and commitment. Certainly, when talking to clients about their search marketing options, we highlight the benefits of the combined approach.

But how can a marketer make conclusive decisions based on these assumptions, and balance their search budget in the way that makes sense for them?

Savvy marketers will look to analysis to find the insight they need. Using web analytics, you can easily find out how you're doing in terms of visitors drawn from natural search. Look for a behavioural analytics solution that can help you benchmark against competitors. This gives you a clearer picture of how you should re-balance your budget to bring you up to speed with the competition. You can measure the sales impact of any increased traffic to determine whether any SEO effort would be worthwhile. Benchmarking also shows when you have a spike or valley in your search -- did the rest of the market have the same experience?

Going further, you can even look at the different roles natural and paid search play in the lifecycle of a purchase or conversion. For example, natural search often has a 'halo' effect on paid search, bringing in visitors in the first instance, before paid search leads them to convert when further along on the buying cycle. This type of '3D marketing' approach, looking at all the influences along the way, can really pay dividends.

Online marketing is increasingly becoming a science as opposed to an art, so the smart choice lies in analytics. This enables you to prove your assumptions and gut instinct, safe in the knowledge that you have the facts on your side. Search for the right answer, and get ready to reap the rewards.

Richard Sheppard is VP and general manager, EMEA, Coremetrics.