Happy Holidays

We’ve had an exciting year – our first! – here at Research Access. So as we pause to celebrate the holidays and put the finishing touches on 2010, we’d like to take a moment to extend our wishes for a happy and healthy holiday season to all of you!

It’s been an exciting year for our industry,  and we know there’s much more to come in 2011. Stick with us for more in-depth and practical coverage of market research trends, tools and techniques. Until then, have a wonderful holiday season!

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Highlights from the Sawtooth Software Conference 2010 – Day 4

Day 4 is a half-day, but it had some very serious papers and great discussion – the marketing science community is alive and well here!

Modeling Demand Using Simple Methods: Joint Discrete/Continuous Modeling (Tom Eagle, Eagle Analytics of California)

  • Discussed 4 approaches volumetric modeling (find out not only “what”, but “how many” of something respondents prefer.
  • Examined Regression Models, Choice Models, Economic Models, and Joint Discrete/Continuous (D/C) Models, with a focus on the latter.
  • D/C Models estimate in two stages: first fit an allocation Multinomial Logit model, then fit a general linear volume model using predictions from stage 1 as independent variables.
  • Compared all methods on 4 relatively simple datasets.
  • Summary of comparisons: Choice Modeling performs as well or better than the joint D/C models.
  • Conclusions: Joint D/C volume modeling is a valid approach to modeling complex volume models.  Because all these techniques occur on the back-end, you can design your study the same way and try out different approaches once data is collected.

Recent Developments in PLS Modeling: An Application for Customer Loyalty and Retention (Stuart Drucker, Drucker Analytics)

  • This talk was about predictive analytics, specifically key driver analysis
  • The way NOT to solve this problem is using stepwise regression (TAKE NOTE: lots of people still do this!).
  • Discussed Partial Least Squares (PLS) Regression and PLS Structural Equation Modeling (PLS-SEM).  In these approaches, factor analysis is web with regression analysis into a unified (more confirmatory in the case of PLS-SEM) framework.  Better manages common issues including multicollinearity.
  • Conclusion: The decision of which model to accept is a philosophical one, depending on whether the ultimate focus is estimating a system of effects (including Customer Satisfaction and the Key Drivers) – use PLS-SEM, or if the focus is maximizing the explained variation of Customer Retention – use PLS.

A Head-to-Head Comparison of the Traditional (Top Down) Approach to Choice Modeling with a Proposed Bottom Up Approach (Don Marshall, TVG, Siu-Shing Chan, Univ. of Pennsylvania, and Joseph Curry, Sawtooth Technologies)

  • Huge effort involving lots of people to set up this experiment.
  • Based on Jordan Louviere’s recent assertion  (2009) that when using HB to measure preferences that we were just capturing respondent inconsistency and that we needed to stop modeling the way most people currently are.
  • Compared current gold standard (Hierarchical Bayes (HB)) where individual preferences are influenced by group averages (called the “Top-Down” approach), to the “Bottom-Up” approach that examines individual preferences independent of group averages.
  • In Top-Down, respondents see different choice sets and choice the best, with a dual-response none follow-up, and are shown fewer screens.
  • In Bottom-Up, respondents all see the same choice sets, they choice top choice, last choice, and whether all/some/none are acceptable, and are shown more screens.
  • Conclusions: while the design and analysis criteria for bottom-up continue to evolve and improve, this analysis provides no compelling reason to recommend bottom-up over top-down at this point.  Interview length and completion rates favor top-down.

HB-CBC, HB-Best-Worst or No HB at All? (Ralph Wirth, GfK Group) – Note: this paper won “best paper” for the conference.

  • Concerns have been raised regarding CBC-HB, and this paper used Monte Carlo Simulations and 4 real-world datasets to find out if the concerns were justified.
  • The Best-Worst idea in CBC is gaining interest – the idea is to show profiles and have respondents choose not only their most, but also their least preferred option.  Compared this approach to standard CBC-HB and also a Louviere approach which asked for most preferred, least preferred, and an in-between choice, and did NOT use HB for analysis.
  • Conclusions: no model was consistently superior based on fit.
    • The Louviere approach is worth considering when data conditions are good and/or the focus is on share prediction rather than prediction of individual choices.  Purely individual estimation makes it much simpler than HB approaches but seems detrimental when data conditions are sparse.
    • The HB approach has good overall performance also under sparse data conditions, there is no negative influence of individual-specific error variances, and the results suggest that the use of additional preference information from worst-choice leads to better estimations, as Best-Worst CBC-HB is consistently superior to standard CBC-HB.
    • Discussion: lots of opinions here, but some main take aways are that:
      • HB will not fall out of use anytime soon, as it appears to perform well under a number of situations.
      • We need to model (simulate) against real-world outcomes whenever possible.
      • Best-Worst CBC is emerging as something to keep exploring, however, there is potential to get into a lot of trouble during the analysis, and there is no commercial tool that provides a solution (other than doing completely custom-programmed analytics).

Conference Conclusions

  • If you are involved in doing conjoint analysis, or other varieties of research that seek to understand preferences and choice behavior, this conference is a must attend.  The top minds in the field are all here and they are pushing the boundaries to achieve better measurement of choice behavior.  The conference occurs every 18 months, and information can be found at www.sawtoothsoftware.com.
  • Note that Jordan Louviere, a key discussant at the conference, was the recipient of the AMA 2010 Parlin Marketing Research Award.  See his interview in the 9/30/10 edition of Marketing News.
  • Plus, the food was really good :)

Highlights from the Sawtooth Software Conference 2010 – Day 3

For the morning sessions, the main conference was joined by the attendees of the conjoint analysis in healthcare conference that is running here in parallel.

The Value of Conjoint Analysis in Healthcare for the Individual Patient (Liana Fraenkel, Yale University of Medicine, VA Connecticut Healthcare System)

  • Looked at conjoint as a way to elicit patient preferences in low certainty situations.
  • Research shows that eliciting patient preferences can have some positive effects.
  • Conjoint analysis is a natural fit, given the trade-off approach.
  • Used Adaptive Conjoint Analysis to provide individual-level interviews.
  • Also looked at using MaxDiff, although it appeared that some respondents had difficulty with the best-worst trade-off, therefore tried a best-only approach.
  • Pros = works at the individual patient level, can handle lots of info, can provide immediate feedback, trade-offs are like real life, discourages rating all features equally
  • Challenges = hard to get independent attributes, hard to specify levels of attributes, have ranges of levels, have dominant attributes, can be difficult for respondents.
  • Reality = patients so rarely are given choices that they don’t know how to react, MD buy-in, discordance between patient preferences and what MD things should happen.

Tailoring Treatment Based on Preference Values (Marsha Wittink, Univ. of Rochester School of Med, Univ. Of Pennsylvania School of Med)

  • Goal was to use conjoint to identify which attributes of treatments are most important to help design better interventions.  Focus here was on patients with depression.
  • Used Hierarchical Bayes to calculate individual level utilities, and also used latent profile analysis to look for unique groups.
  • Did find unique groups preferring different treatment modalities.
  • Plan to use data to assess whether these preferences are better predictors of treatment uptake than other demographics.  Could also use to tailor treatments.

Conjoint Design Effect on Respondent Engagement (Paul Johnson, Western Wats)

  • Looked at CBC tasks with 20 vs 30 cards, and also at Adaptive CBC – looked at placement of conjoint task before or after other survey questions.
  • No differences in the way respondents answered other questions based on type or order of conjoint.
  • Purchase intent higher with ACBC task – might put respondent more in the mood to buy.
  • Respondents did NOT speed through the rest of the survey after doing the conjoint first.
  • Time spend on conjoint task longer for ACBC.
  • Few to no differences in measures of consistency, hit rates, or error levels in model.
  • ACBC did best job of predicting a winning holdout concept.
  • Other benefits of ACBC: get explicit rules of non-compensatory rules made by respondents, get more stable model estimates with smaller N’s.

Sales Promotions in Conjoint Analysis (Marco Hoogerbrugge & Eline van der Gaast, SKIM Analytical)

  • Looked at the best ways to present price promotions for testing in conjoint analysis.
  • Ideas of ways to display:
    • Original (gross) price + % or $ off.
      • When model, need to assign levels to final price.
  • Original (gross) price NOT shown, promotion (net promoted price) only thing shown.
  • Original (gross) price + promotion price shown and highlighted.
    • Could model just net price, or keep original price as main effect, or include interactions between original and promotion price in model.
    • Modeling would benefit from data about purchase behavior – more external data.
    • Note that you’ll need to model differently based on which approach you take.

How Many Questions Should You Ask in CBC Studies? – Revisited Again (Jane Tang & Andrew Greenville, Vision Critical)

  • Past (and more recent) research
    • Johnson & Orme (1996): ask up to 20 tasks; in later tasks brand becomes less important, price more important, and more likely “none” choice.
    • Hoogerbrugge & van der Wagt (2006): increase in hit rate after 10-15 tasks is small; complexity of study more influences hit rate.
    • Markowitz & Cohen (2001): HB hit rates not greatly enhanced by increasing sample size; more choice sets better than more sample.
    • Suresh & Conklin (2010): complex survey design leads to lower respondent engagement; more complex attributes leads to choosing “none” more often and more price reversals.
    • Hauser, Gaskin & Ding (2009): Non-compensatory rules used when more time pressure, more products, and more familiarity with the category.
    • Current study looked at 3 conjoint tasks: 6 cards with 3 options, 15 cards with 3 options, and 15 cards with 5 options.
    • Conclusions:
      • Increasing the # of tasks gave limited improvement in prediction ability, but at cost of slight deterioration in sensitivity and consistency.
      • Simplifying behavior occurs in later tasks – more likely so when respondent familiar with the category.
      • Increasing complexity of task (showing 5 vs 3 options) doesn’t help anything.
      • The balance is this: sometimes, individual level models don’t converge when have small # of tasks, so need to ask more tasks to get precision, but as do so, reliability goes down – need a balance .

The Strategic Importance of Accuracy in Conjoint Design (Matthew Selove, USC, John Hauser, MIT Sloan)

  • Looked at what happens when we have “noise” in a sample versus “heterogeneity”
  • Noise leads to less differentiation in product decisions, whereas heterogeneity encourages differentiation.
  • Compared a “well” and “poorly” design conjoint study.
  • Poor designs lead to more noise, which leads to inconsistency in the conjoint task and less ability to validate to hold-outs.
  • Need to accurately estimate randomness.  If you have no hold-outs to validate against, Louvierre recommends tuning model to an exponent of 0.4.

Product Portfolio Evaluation Using Choice Modeling and Genetic Algorithms (Chris Chapman, PhD & James Alford, PhD, Microsoft)

  • With conjoint data, we know how to optimize a product, but what about a product line?
  • Took CBC and ACBC data, derived individual-level partworths using HB model, iterated using a genetic algorithm to fit many portfolio preference models, and inspected.
  • Took 1080 possible products (based on 9 attributes with 2-7 levels) and found that after 6-8 products in the portfolio there was no more increase in share of preference.
  • Also asked which products appeared in a large number of winning portfolios – found a couple “new” products this way.
  • Other findings: CBC had much noisier price data than did ACBC; ACBC has more stakeholder face validity, smaller sample sizes needed, and better respondent engagement.

The Impact of Covariates on HB Estimates (Keith Sentis & Valerie Geller, Pathfinder Strategies)

  • Note: this presentation and the next were probably the most controversial and shocking to most of the conference participants.
  • Method: estimate HB partworths with and without a covariate, compare the quality of the two sets of partworths; do this for several different covariates, one at a time.  Looked at 3 classes of covariates: demographic variables, category behavior variables, and attitudinal variables.  Measures of fit and predictive accuracy included: RLH, Hit Rate, Holdout Likelihood, and MAE (error).  Measures of partworth variability included: importance spread and standard deviation ratio.  Ran across 5 datasets.
  • Conclusion: NO lift in predictive accuracy by using covariates; did see some increase in partworth variability.
  • Discussion: should covariates be in our tool kits?  This paper says NO, but why might we want to include them?  Carefully chosen covariates can provide insights by subgroup.

Added Value through Covariates in HB Modeling (Peter Kurz, TNS Infratest Forschung GmbH, and Stefan Binner, bms marketing research + strategy)

  • Since HB assume one single multivariate normal population, can get “shrinkage” of respondents  toward the population mean, and therefore segment differences could be reduced.  So, how about adding covariates into the upper level model?
  • Method: looked at 10 commercial studies, 30,000+ conjoint interviews, B2B, B2C, worldwide; looked at natural (demographic), segmentation membership, and intention or past behavior data as covariates.
  • Conclusion: they ran all kinds of models, from standard HB to HB with covariates to Latent Class, etc., and HB with covariates did better only on 2 studies.
  • Recommendations: ensure sufficient sample size, use standard HB, use hold out tasks.
  • Discussion: If have clearly defined clusters, covariates could help; more heterogeneity can help with market share projections, line extension and optimization decisions, estimates if willingness to pay, and it helps IIA (red bus-blue bus problem).

Regarding these last two papers, everyone really wanted to believe the covariates could helpful, but the evidence argued against improved predictive accuracy by using covariates.

The Problem with Neuromarketing….

There are several problems really. The first is the name. It should really be called applied cognitive neuroscience (ACN), because that is what it is. Hopefully this would counter all the specious arguments about it being scientific. The New Scientist (http://www.prnewswire.com/news-releases/neurofocus-and-new-scientist-magazine-apply-neuromarketing-to-select-cover-design-100053049.html) test raised some comments about the science of ACN. I have to disclose in what seems like a previous life I studied cognitive neuroscience (we called it neuropsychology back then). Trust me, it is a science, it has been around a *long time*, many decades, and it also uses statistics correctly. This latter fact is a novelty for a lot of MR, I know. At least ACN tries.

There is also the privacy “discussion”. ACN is about as invasive as looking at someone who is blushing and deducing they may be embarrassed. ACN measures physiological correlates of mental states or processes. It happens to do them via electrical signals measures from the brain. We do this all the while with body language, speech tones and so on. Just because there is a lot of equipment in ACN and latin words doesn’t make it any different.

The biggest problem ACN has is sample size. N = 19, as in the New Scientist test, isn’t much. It is barely enough for a single quota cell. Making big decisions based on tiny samples mostly ends in tears. The sample size issue relates to the technology of ACN. The electrodes on the scalp can take time to set up and this limits sample sizes. However several companies have ways round this with either limited electrode placement (not so good – one electrode gets you nothing except muscle noise) and less “invasive” caps that hold the electrodes on the scalp without glue. The latter holds the most promise so far as I can see. Sample size is a solvable problem, scalability may take time, but compared to the rest of the technology used in ACN it is not the most complex problem. Several companies are building normative databases which will be hugely useful.

The problems with ACN are solvable, the potential is huge…

Getting to Know You

Allow me to introduce myself. My name is Joshua Hoffman, and I work for you.

I’m very excited to be joining Research Access as the new Editor-in-Chief, but when I say I work for you, I mean it. My role at Research Access is to bring you the latest, most interesting, innovative, and exciting information that exists in the market research industry. My hope in the end is to challenge and inspire you, to spark the discussion of new ideas, and to build a richer market research community, which I know would benefit us all.

Of course, what kind of market researcher would I be if I didn’t include a MicroPoll in my first post? Please share your thoughts below, but also, please consider leaving your comments on this post, describing what you’d like to see from Research Access in the future. Your input and feedback will be paramount in shaping the topics, authors, and resources you’ll see from Research Access going forward.

Cheers,
-Josh

Spotting Talent

Great interviewers say  they know in the first 10 minutes whether a candidate is fit for a role. I can attest to this, having interviewed hundreds of people for different jobs over the course of the last 15 years. Similarly, great candidates know immediately if they have found a connection with the person interviewing them; chemistry can be clear instantaneously.

Well, so, I consider myself a great interviewer but I also know I’ve been deadly wrong many times. While I have a good batting average, I’m no Ted Williams for sure. I’ve been too hasty at times and too excited at times. I’ve been beguiled by smooth talkers who can’t execute worth a shit. And so on.

I’d love to know what RA readers consider the top qualities in people they recruit (or in their peers) and how you detect these qualities quickly. And how do you deal with it when you know you’ve been duped?

Let us know.

Two Common Times NOT to Use Conjoint

This information is useful for people who want to understand a couple times when it is not appropriate to use conjoint analysis.

Conjoint analysis is a gold standard technique for measuring feature preference, particularly in relationship to price.  I’m particularly fond of Adaptive Choice-Based Conjoint (but that’s a topic for another post).  There’s a lot of buzz around conjoint as a tool to help product managers choose features that will help their products better compete in the marketplace, so I often get calls from companies thinking it would be a good idea to do a conjoint project.

In this post, I’ll show two common times when it is NOT appropriate to use conjoint analysis.

Definitions:

An “attribute” is something like brand, number of licenses, amount of storage, color, package size, etc.  A “level” is the degree of an attribute.  For example, brand A, B or C; 5, 10, or 20 licenses; 1, 2 or 3 TB of storage; blue, red, or black color; 12 ounce, 18 ounce, or 24 ounce package.

When NOT to Use Conjoint:

1. Your product features are already locked in – you just want to test prices. If your product is fully baked, you don’t want to use conjoint.  Conjoint is all about looking at the inter-relationship between various levels of product attributes and price.

If your product is locked in as a 10 license product with 1 TB of storage and other features set, conjoint is not for you.

So, how can you test price on your fully baked product?

Note: each of these methods deserves its own post, but here’s a taste.

Monadic designs:

  • Break your respondent sample into groups that each see a single price associated with the product and ask their likelihood to purchase.  Plot the probabilities against the prices.

The  van Westendorp Price Sensitivity Meter:

  • Ask “too inexpensive”, “inexpensive”, “expensive”, and “too expensive” questions.  Plot the data to obtain lower and upper bands and optimal price point.

The Newton-Miller-Smith variant of van Westendorp:

  • Add purchase probability follow-up questions based on the inexpensive and expensive answers.  Build consideration curves.

2. Your attributes don’t vary (don’t have levels) – you’re just testing preference/importance of a number of items. You are not looking at the inter-relationship of various levels of brand, size, quality, durability, package, price, etc.  Instead, you want to understand the importance of, or preference for, a number of features/attributes that each have a single (constant, not varying) level.  Perhaps you want to test the general importance of brand vs size vs quality, etc.  Or, you may want to understand the importance of the specific, fixed features that make up your product (e.g., is having 10 licenses more important than having 1 TB of storage or the other features that make up your product?).

So, how can you test preference/importance of these features?

Note: A full description of MaxDiff can be found on the Outsource Research website.

Maximum Difference Scaling (MaxDiff)

  • Force respondents to make trade-offs between (usually) 4 of your items at a time.  They indicate which item is most and least preferred (important, etc.).  The output yields all the items on a 100-point scale, where you can truly say that a given item is “twice” as preferred as another item with half its value.

Note: MaxDiff can be used to help reduce the number of attributes that you carry forward into a conjoint.  For example, if your product has a lot of potential features to test, it would be wise to reduce the number that you bring into conjoint, so that the respondent is not overwhelmed.  MaxDiff can show you the most important attributes, which can then be further explored in the conjoint.

Conclusion:

Conjoint analysis is a powerful technique that can help you configure your feature-price mix to create a product that will be most preferred by your market.  However, if your feature set is already locked and you just want to test prices, or if your attributes don’t have any variation (levels) to them, then conjoint is not for you and you’ll need other techniques to solve your research problem.

CrowdSolving – Beyond CrowdSourcing?

I’m not very convinced of the “wisdom of crowds.” There are numerous examples of how “the wisdom of crowds” is in fact the “idiocy of the mob.” Look at some political movements or some of the more extreme religions, for instance: a good few of these make no sense, but they have a lot of people who believe them. In Vanatu, an island in the Pacific, there is a cargo cult called the John Frum Cult that thinks building replicas of USA air force bases from World War II will bring the USA and all their goods back to the island. A lot of people believe this.

There is a lot of research from social psychology showing that groups polarize decisions in contrast to individuals. A group will make a more extreme decision (cautious or risky) than an individual. There is also the fact that estimations of physical sizes and weights will tend to show a normal distribution, with the most common estimate, the mode, being the correct one. Here there is wisdom in crowds, or more likely the wisdom of the normal distribution, the central limit theorem and statistics in general. Distributions are wonderful things.

One of the advantages of a large scale survey is that you are able to leverage a lot of people’s experience and knowledge. Recently, a company called “Netflix” in the USA utilized the web and their subscriber base to solve an interesting problem. While it is not the usual meaning of the term the “wisdom of crowds,” it is an example of how a crowd can solve a problem. Netflix (www.netflix.com) rents DVDs to their subscribers. They send the rentals via mail and their users maintain a list of which DVD’s they want. Netflix also tries to predict which DVDs people might like to watch based on the DVDs they have already rented. Amazon does a similar thing in making product recommendations to purchasers. Netflix wanted to improve their predictive algorithm by 10%, which is quite a large improvement. They could have tried to hire all sorts of geniuses, but they instead chose a very unique way to solve the problem. They set up a web site (www.netflixprize.com), posted a huge data set of movie DVDs, data about those movies, and subscriber choices. They then offered $1,000,000 to anyone who could improve their algorithm by 10%. There were two conditions: a deadline (September of 2009) and an agreement that anyone who submitted a solution had to document that solution publicly. Many companies allowed their employees to set up teams and compete, some individuals competed, and teams merged and re-formed over time. In the end there was a winning team: Bellkors Pragmatic Chaos.

In this case the wisdom was not “crowd think,” whatever that is. Instead, Netflix leveraged the web and all the people surfing it to source people who wanted to solve this problem. For Netflix, the $1,000,000 was cheap. They could never have afforded to hire all the people who took part in the contest. They got access to world-class computing facilities, superior minds, and  they received some great publicity as well.

The winning algorithm was a technique called a “Restricted Boltzmann Machine.” It proved that numbers and math matter. It wasn’t the crowd that solved the problem, but the crowd was the mechanism that made the solution possible. I’m inclined to think that this is the real wisdom of the crowd. People can come up with all sorts of strange beliefs; the ability to get people to address your problem is the wisdom of the crowd. It’s another example of how the web has changed the world in a radical way. Twenty years ago, it simply would not have been possible for Netflix to find a solution to their problem so gracefully. I hear there is going to be another Netflix contest. It’s nice that it was the math that was wise in the end….

Online Survey Sample Is Not Clean Enough – Clean it Yourself

This information is useful for people who use panel sample for online surveys, and who want to make sure their survey data is truly clean.

Online Survey Panels Tell Us Their Panelists Are Clean

It’s hard to open a marketing magazine without seeing an ad from an online survey panel company proclaiming how clean and high quality their panel is.  A few years ago, this claim was a big deal – it was the Wild West of online survey panels, and buyers of sample had to be very careful as to who they worked with.  Today, however, most major online survey sample companies have adopted measures to get rid of professional respondents, prevent over-surveying, and make sure that respondents are who they say they are.  So, whether the sample is “true” or “pure”, or there’s “attention to detail”, most reputable panel companies are doing a decent job of giving those of us who field surveys a good product.

But Survey Data is Still Dirty

However, and here’s a big however, the data from most online surveys using panel sample still comes in with some dirty responses.  My research shows that between 1 and 5% of survey data from panel sample is garbage.  Garbage – throw it out; don’t bring it into your final dataset to analyze.  Sure, one can blame some of these dirty responses on frustrated respondents dealing with poor survey writing (bad questions, too long, etc.), but the fact remains that you had better clean that survey data before it goes in for analysis.

So, How Do I Clean the Data?

Here’s a plan you can use to clean your data.

When I say “flag” below, I mean that you create a new variable in your dataset next to the variable you are examining, and you place a “1” in a cell if the respondent’s case is flagged.

  1. Flag speeders. Look at time to completion and flag those respondents who took the survey in an unrealistically short time.  Check the median time to completion and establish rules that you feel comfortable with – I often flag those taking <1/3 of median time with a “1″ (“speeder”), and those taking < 1/4 of the median time with a “2″ (“super speeder”).  You might consider removing outliers (at the slow end) before calculating your median.
  2. Flag straightliners. If you having any grid/matrix questions, flag those respondents who gave the same response to every item (unless it makes sense that they could do so).
  3. Flag gibberish or garbage responses. If you have any open-ended responses, look for text such as “asdf” or “…..”; flag these responses, and any other “colorful, yet meaningless” responses you find.
  4. Flag incongruent combinations. If a respondent says their company size is 1000 and the number of PCs in the company is 5, something’s wrong here.  Flag it.
  5. Trap questions. Did you include any questions such as “Please choose the third response below”, or “Please type the word “attention” below”?  If you did, check them, and flag those respondents who didn’t follow the directions.
  6. Sum up your flags. Compute a new variable that sums all the flags.
  7. Sort your dataset by summed variable. Bring cases to the top that have suspicious answers on a number of your checks.
  8. Inspect and delete cases with flags. Delete those cases that are too “dirty” to be included.  Review with key stakeholders to agree on deletions.
  9. Notify your vendor of any bogus respondents. All the vendors I work with do not charge for any respondents I have flagged for deletion.  Show them the IDs of the respondents you threw out, and they’ll take action on their side to warn and/or remove these panelists from their database.

Following the steps above will insure that the data you analyze is as clean as possible.  Yes, it takes a bit of time, but the effort is clearly worth it when compared to making decisions based on the analysis of data that includes bogus responses.

One last note: if you really need your final sample size to hit a specific number, and you can’t go below that number, you can over-sample, in anticipation of throwing out some respondents.

Feel free to contact me for more details about some of the specific techniques I have found useful to clean data, or follow me on Twitter @NicoPeruzziPhD to hear about other marketing research topics.