Time to buy or not index

I have been working for a few months on some kind of index to give an idea of when is a good time to buy a property.

For many years I have been advising my clients on my take on the housing market. I feel my views on the market go deeper than the lender surveys as my views are based on a number of additional factors.

1 - lenders lending practices that are not understood by lenders! (lie to buy, liar loans, fast track)

2 - buyer sentiment. You can't beat sitting down face to face with someone and talking to them about their feelings.

3 - forums. Many different angles an data are presented in a range of internet forums.

So my Time to Buy index is based on the following

The over or under value of property based on price, mortgage rates available for buying and letting and rental income.

Market sentiment and direction of sentiment.