A rationale is a justification of something. This explains why you are taking an action or proposing an idea. All research requires a rationale, whether it is to compare car insurance for the best deal which suits you, or to save money on travel costs to and from work and your place of study.

In association to the Association of Research Ethics and the Ethics Research Council, the UK government also provides advice to businesses on how to conduct market research.

 The rationale should include the focus, methods and means for conducting the study and the outcome being sought. This does not mean you make the research findings fit what you want to promote, but that you have a well thought out plan which supports the reason for conducting any form of research.

We have started to explore the interpretation and use of data. Interpreting data is subjective, therefore rigorous steps for checking the validity etc must be well planned and implemented. 

To analyse the data, the it must be interpreted to find its meaning. For example, if a customer states they like the taste of a new packet of crisps, what does that actually mean. They might not like it enough to buy it or switch from their current choice. They might have other preferences or feel compelled to give a positive response. They might even prefer a competitor's product or flavour. Without asking the right questions  the meaning can offer little value.

Analysis requires a detailed examination of the data in preparation for interpretation. Data come in many forms, not just numbers such as:

• images

• observations

• audio and video recordings

• reports

• case studies

To analyse numbers, you can use software such as spreadsheets and apply formulae or, on a much smaller scale, it may be sufficient to use manual calculations. Whatever data type, analysis involves breaking down the data into smaller and smaller particles to explore meaning and find patterns and trends to establish the headline information.

The use of data must inform the rationale for the research. To make a valid marketing decision a business may want to explore customer reasons for upgrading equipment such as their mobile phone. Some customers may change mainly for the quality of the camera while another may need a larger display for reading messages. Other information such as amount of use or capacity may be irrelevant to the business at this moment in time.

To support the market research and validate its results, the market research may require additional sources of information to satisfy the reliability or sufficiency of the data gathered. Depending on the type of research undertaken, further sources might include:

• Government statistics

• National economic statistics such as from the Office For National Statistics (ONS)

• Global statistics such as from the the Organisation for Economic Co-operation and Development (OECD)

• Environmental factors such as those related to food, environmental or rural communities.

• Academic Research articles and journals, which may contain more current information than that found in books- it takes a longer time to produce and publish a book.

In the case of a major government project such as the High Speed 2 Rail Route (HS2), market research has been ongoing since its inception. The public and various bodies have contributed their views and arguments both for and against its implementation on a massive scale.

The information obtained should be evaluated for its reliability and validity by, for example, finding other sources or further information to support or discredit the data or findings. A thorough evaluation aims to find holes in the research by rigorously testing the robustness of the entire study. To evaluate information obtained, methods include:

• Involving others and asking them to critique the findings

• questioning its sufficiency, accuracy etc

• assessing the pluses and minuses (What works well and what needs improving)

• questioning what the information does not tell you

• identifying improvements 

The product life cycle concept reflects the theory that products or services follow a cycle just like people. They are born, grow up mature and eventually die. It is a useful concept for thinking about what a product has achieved and where it is heading in the future.

A rationale for market research is to seek opinions about customer preferences, the products or services they value and why, where improvements might be made and the reason why some products lose favour when others do not. The stage of the product life cycle a product is in may influence the marketing of that product

Introduction

In the introduction stage a product takes time to find acceptance by purchasers and there is slow growth in sales, just as market research takes time to plan, evolve and receive approval. With a new product only a few organisations  are likely to be operating in the market, each experiencing high cost because output is low. A business may charge high prices to cover research, development and the initial promotional costs, but even then profitability may be difficult to achieve.

Growth

If the product achieves market acceptance then sales grow rapidly. In this growth stage, profits begin to materialise as higher production levels  reduce unit costs. However, the growing market attracts competition and soon producers have to invest in building a brand image, product improvements and sales promotions to obtain a dominant market position.

Maturity

The maturity stage  follows when a product experiences stable sales. This is generally the longest period of a successful product's life. Nut eventually sales fall and the market finds itself with too many producers who begin to suffer poor sales and falling profits.

Most products research the saturation stage when sales begin to fall. During this period some brands will leave the market. The same is true of market research and the length of time the findings remain current, and therefore of value is variable.

Decline 

Products reach a stage of decline when sales fall significantly. Organisations progressively abandon the market, sometimes leaving a few producers who are able to trade profitably on low sales totals. Organisations use the product life cycle to devise new product plans. An organisation will look to introduce new products to coincide with the decline of the established ones or introduce product extensions by adding to the line-using the brand to provide credibility or imply necessity or need. Two examples are outlined below.

Line Extension

A line extension is where a product is extended by adding a new colour, flavour or size of packet. An example would be Cadbury and Mars who introduced fun size bags- these are line extensions because the product in the bag is a smaller version of their popular snacks bars.

Brand Extension

A brand extension is where a well-known brand extends its range to a different product, such as Next Homeware, or the extension by Richard Branson of the Virgin Records Label brand into transport and telecommunications. M&S extended their well known brand into financial services, as have several other brands. Globally known Dutch giant Philips have been extending their brand since inception in 1891.

This is a useful link with a case study on Apple: 

https://www.geeksforgeeks.org/product-life-cycle-plc-stages-and-case-study-of-apple/