SIMALTO – SImultaneous Multi-Attribute Trade Off – is a survey based statistical technique used in market research that helps determine how people prioritise and value alternative product and/or service options of the attributes that make up individual products or services. A particular specific application of the method is in political science. It can be applied to predicting which of the alternative combinations of optional service benefits provided by a local authority, state or national government in their annual budget would meet with the ‘maximum’ approval of a target population.
Survey design SIMALTO is based on creating a matrix of the options that can combine to form the product or service. Each row of the matrix represents an attribute and the matrix columns are the various options (alternative features, levels of service, benefits) of that particular row attribute. Each option is associated with ‘cost points’ which indicates how much more or less that option costs to deliver than the other options on the matrix. The cost points may reflect the actual price in currency, say, of a consumer or industrial product option, or, more commonly in service applications, the relative costs to the supplier of delivering the different benefit options.
Example SIMALTO Matrix : To improve from 8 hours service response time to 2 hours would ‘cost’ an extra 10 points. This would be twice the cost of improving from 6–10 days wait for spare parts to a 3-5 day wait. Respondents complete a series of tasks on this matrix. These may include indicating the option on each row he currently perceives he experiences in the product or service he has now and/or his perception of a rival product or service performance. But the main tasks completed on the matrix are the respondents prioritisation of the options within total ‘constrained’ budgets. The respondent is given a total number of ‘cost points’ which he allocates to the options on the matrix to ‘design’ his preferred total specification within that total given cost constraint – called his first priorities. Then he is given more cost points to ‘improve’ his first budget allocation to show his second priorities. Typically there are a minimum of three prioritisation stages and rarely more than five. These priorities can be used to create market models that estimate potential market share of alternative product or service specifications. This staged prioritization of options was first developed by John Greene while he was the international market research manager at Rank Xerox in London in the mid-1970s. A simpler questionnaire, where the respondent only allocated a single total budget across many of the various matrix options available, to build his ‘personal specification’, was used by Ford Motor Company in Detroit in the late 1940s. More recently this single stage budget allocation approach has been used by many manufacturers on their web-sites to collect a given respondents preferred specification having been shown the costs of different options. Also this single budget allocation, without the multiple prioritisation stages, is a part of some variants of modern conjoint trade-off analysis. The algorithms required for the modelling predictions of SIMALTO data enabling potential market share calculations and needs-based analysis were first created in the early 1980s, with major improvements and extended capabilities introduced in 2000. If applicable brand can be regarded as a product attribute, but for SIMALTO market simulations, brand value information is not collected in the same way as the trade-off options of the product or service specification. Rather a variant of Brand-Price Trade-Off is used. Total specification price or cost is not treated as one of many specification variables, as in conjoint studies, but treated mainly as a constraint. SIMALTO Modelling is part of the set of trade-off analysis tools used for systematic quantified analysis of decisions. These tools include the various forms of conjoint trade-off, discrete choice modelling and brand-price trade off approaches.
Survey administration The visual presentation of the matrix of attributes and their options is the key component of SIMALTO studies. Originally these were presented on paper, often in A3 size in Europe or ‘Legal’ size in the USA. The larger than usual paper size was required to comfortably show all options simultaneously to the respondent. The simultaneous element ensures trade-off priorities are collected in the context of the total specification and each options cost portion of the constrained total cost is always ‘in view’. Respondents used different coloured pens to indicate their different stages of priorities. The questionnaire can be presented by an interviewer face-to-face with the respondent, or in a ‘focus-group’ situation where all participants individually completed the various SIMALTO stages under the guidance of a single moderator. The limit on the number of attributes is not constrained by mathematical issues, but rather dictated by common sense of what a respondent can sensibly deal with in a particular product field and in a reasonable time period. Up to 20/25 attributes, each with up to 4 or 5 options is possible. However, in studies that have fairly simple options with short descriptions of alternatives, e.g. banking charge cards or contract options for telecoms services, up to 35 attributes can be included. Studies including attributes where differences between options require more detailed explanations, perhaps with illustrations, mean that 15-20 attributes might be a practical limit. Since 2000 the majority of SIMALTO studies have been completed via the web. This reduces data collection costs considerably but has the disadvantage that the whole of a matrix with 10 or more attributes cannot be viewed simultaneously without scrolling the matrix on the screen. This disadvantage means that 20 is a realistic maximum attribute number on the web, unless respondents are sufficiently motivated (by product interest and/or incentives) to spend longer than 20 minutes completing the questionnaire.
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