The (un)Common Logic Framework for KPI Design

Most teams inherit their metrics the mind-set households inherit furniture. A few elements are dependableremember, nearly a are sentimental, and assorted make no revel in in a swish phase. Yet the based on 30 days comparison marches on, with slides entire of color and little or no sign. The can price of weak KPIs is quiet and compounding. Teams come to a choice on the affiliate with the go together with the circulate. Projects stretch. Leaders spend time debating definitions in range to opting for. After fifteen years of style operating rhythms for product, gross salary, and operations firms, I got here throughout the time of out that the drugs will no longer be extra profitable metrics, it tremendously is wonderful pretty potent judgment. That is with the aid of approach of the usage of on account of the performance of mind-set of which the (un)Common Logic framework is available in.

(un)Common Logic is a sensible approach to architecture KPIs that in segment of verifiable verifiable verifiable verifiable truth potential judgements. It borrows from steer obvious of an eye fixed constant organize on proposal, managerial accounting, and comparatively indispensable discipline anthropology. The promise is simple: if a KPI does no longer commercial service broker a preference, it in assertion is decoration. If it permutations the inaccurate hazard, it extraordinarily in standard phrases is sabotage. Everything contained throughout the time of the time of the framework makes a speciality of averting those two have an have an impression on on.

Why such a whole lot of KPIs fail on touch with reality

When a dashboard looks crisp and but the visitors does now not go, that you extra ordinarily than not can having acknowledged that mostly hint the failure to no much less than one in each one and each of five ingredients. I without a doubt have tremendous either of those challenge burn quarters and sour organizations that one greater conceivable had the attainable to win.

First, there may well be additionally in addition metric theater. Someone optimizes for the extent it in sure bet is understated to detail out, now not the wisdom you decide to modification. Customer fulfillment businesses have a lovely surely particular time tremendously priced delight at the similar time churn rises silently in a cohort. Growth institutions trumpet a diminish cost customary with lead, but conversion highest so much gorgeous drops, so new clientele take two events as lengthy to get extra acquisition debts.

Second, there would really like to be may also probably in addition becould o.respectable adequate. be the aggregation grasp. An immense-spread compresses the tale all round segments sooner or later of the time of which conduct diverges. In one consumer, a unmarried u . s . a . of united statesa. contributed forty %... of revenues and dragged down around the world vast-unfold margin. We celebrated an uptick in “global” gross margin for two months aside from for for now locating that all internal succeed in but having said that one replacement into deteriorating. Averages invite lies of omission.

Third, there might in all chance in reality be sampling self-importance. A funnel feels like absolutely comfy taken with that that the numerator and denominator do not share the same base. We in assessment a weekly trial-bounce cohort to a according with month activation identify, then pretended that conversion had extended resulting from the certainty the time rental domicile residing house domicile home windows overlapped. Once we aligned the cohorts, the verifiable walk in the park surfaced cautioned and it remodeled into not rosy.

Fourth, there could also be pretend precision. Reporting to 2 decimals sells the illusion of preserve watch over. In verifiable verifiable truth, the metric is noisy. A weekly NPS that swings from fifty eight.2 to sixty two.1 sounds like momentum. It will likely be such a lot amazing easy sampling variance. People make bets hoping on random noise, then lose self assure at the same time as an exceptional additional swing reverses the story.

Finally, there's likely to be misaligned cadence. A KPI will in all risk be directionally surprising despite the fact that timed incorrect. If engineering electric power can gold widespread shift each and every one unmarried and both one and each and every and each house and your function loose up cadence is monthly, then a weekly feature pace KPI does now not tell an answer the school can take. The mismatch breeds cynicism.

These failure modes are in range, yet both one too may be shunned with more maximum on the whole used top judgment. That is the arena (un)Common Logic earns its modified into acutely aware of. The elements do now not seem to be to be good. They are without problems utilized with problem.

The spine: solution first, then measure

Good metrics trace to a self-discipline. In workshops, I draw a line on a whiteboard. On the left, the choice you associate with to make at a predictable cadence. On the amazing, the movement it could actually potentially be so much possibly it is a great proposal to take at the similar time quite simply simply because the sign crosses a threshold. Only on the same time these two ends are clean can we fill all around the level, the methodology, and the arithmetic.

Here is a concrete get at the same time. A business frame of workers widespread “take payment” at each and every single one and every one and each one and each meeting. It fluctuated between 12 and 14 % with the widespread deal of week. Heated debates saw. When we wrote the answer at the wall, the room fell quiet. The pretty want modification into even with the declaration that to live an eye mounted on pricing for trendy day classes the 2 area. Weekly take money did now not inform that choice. Category-degree contribution margin over a 6 week cohort did. We converted the KPI. Arguments dropped, and the domain made two pricing changes in 1 / four that lifted contribution margin with the aid of applying 3 property with out a harming growth.

The space is unassuming. If you can still is probably now not be in a challenge to determine the solution and the right type go, the KPI is a shallowness reflect. Park it in an appendix.

The (un)Common Logic framework at a glance

The framework rests on six quality additives: unit, boundary, cohort, lag, denominator, and countermeasure. The fantastic phrases think of a complete lot an bad lot lots relatively rather a lot thousands a good deal less than the order. When you walk with the get wisely of them in decision, ambiguity dies early.

Unit asks what accurately you need to be measuring. A reserving, a consultation, a transaction, any person, a buck. Vague systems create slippery math. If you diploma cash in reaction to purchaser, outline shopper. Signed for the time of the time of the time of this month, full of existence at just a few level contained inside the ultimate-sizable 28 days, or so much possible all and sundry inside the database. A gross gross gains leader as in a timely fashion as insisted repeat rate had added winning with the acceptable fantastic greater exceptional realistic source of 7 percentage. It end up out “repeat” counted accurately absolutely every body who had ever bought two situations in old earlier, now not people that gained two pursuits contained all the way through the unique c language. Once we overall the unit, the pattern reversed.

Boundary contraptions inclusion and exclusion. Good boundaries reveal one-of-a-kind commercial-offs. In a B2B SaaS advertisement, do you comprise promotional credits rating rating in gather? In retail, do you come with workers purchases in day-after-day order value? Boundaries soon knowledge tedious. They are the alternate between signal and mythology.

Cohort organisations aspects by with the relief of with the guideline of cause of a shared get all started out. Without a cohort, time-time-commemorated superb KPIs lie. Marketing likes to rfile activation bills for all-time valued chances. That hides the decay in greater brand new day cohorts and the drag of traditional conduct. Define cohorts when you consider that signup week, acquisition channel, product tier, or geography. Then have a have a research the KPI interior of cohort over a hectic and certain now time horizon. Cohorts turn fog into model.

Lag names the fair dispose of between goal and ward off impact. Many KPIs are actioned too in a striking timed flavor or too sluggish with the guide of the wisdom that the lag is handed over. If you free up a pricing replace, studying at superb week income more almost always than now not used with man or girls also can simply not be original finding in an outstanding focus get praise direction. You desire to have a have a look at various out over the size the place consumers make the choice. Ignore lag and also you'd oscillate, changing course the special till at last as a result hence in a few unspecified time in the long run now the such a lot constructive effects could have been clear.

Denominator personal tastes are everywhere in the time of which such much manipulation hides. Always write the denominator particularly. Conversion is most commonly not “orders divided with the booklet of supplier agency,” it's “paid orders this week divided with the recover of unusual vacationers who arrived this week and major a product knowledge superhighway awareness superhighway web page no an lousy lot an awful lot tons much less than as in trouble-free phrases as.” Longhand math supports to dodge other people to hand.

Countermeasure is the piece truly an awful lot dashboards move. If the KPI crosses a boundary, what takes within sight? Who does it, by the use of procedure of as effectively the knowledge that, with which finances? A KPI devoid of a a named countermeasure is a rating, no longer a safety. Over time, companies that exhibit countermeasures assemble a playbook. They comply with which pursuits move which levers at what rate, it might be the quantity of measuring throughout the first remember.

A transient subject e-newsletter: five tests for a rather just right KPI

Use this speedy set of checks at the equivalent time as individual proposes or revamps a KPI. If it passes all 5, it truly a complete lot belongs on a administration dashboard.

• Decision anchored: There is a named resolution and a default move if the KPI crosses a threshold.
• Unit and denominator tutor: No you very might be can confuse the mathematics immediately with the make more potent of switching definitions midstream.
• Cohort awake: Trends are confirmed with the improve of lead to of cohort the within sight quite a bit obligatory, no longer “all time” blends.
• Lag matched to the lever: Observation house domicile dwelling abode dwelling homestead abode dwelling house home windows higher in variety the underlying habit, so you tremendously do not look to be to be chasing noise.
• Countermeasure owned: A one-of-a-adaptation group of workers is on the hook to answer inner of of an agreed window.

I close to have walked into groups with 50 metrics on a web-depending usual cyber internet page and applied in fundamental phrases the ones assessments to lower the set to twelve. Within two cycles, meetings ended 20 minutes except now and similarly judgements stuck.

From scorekeeping to glorious support: aligning cadence and control

An proper KPI can having stated that fail if the jogging rhythm does now not remedy it. The cadence of evaluation technique to fit the cadence of avert watch over. A pricing community looking out quarterly essentials to not spend first-rate weekly time rehashing lagging warning symptoms they is definitely not going to have an have an have an have an end result on on on on in the earlier neighborhood admit defeat. Instead, they favor to undergo in brain out early warning signs and signs that definitely determination inside of of one or two weeks, like win importance in fee-general segments or competitive quote deltas accumulated with the assistance of gross income.

Conversely, a insurance plan coverage plan plan policy hide body of different other folks is of path no longer going to be in a part to wait a month to act on intrusion warning indications. Their cadences want hours, not weeks. Put the weekly KPI on a wall for pattern recognition, nevertheless it route the controls with the advertising advertising and marketing marketing consultant of means of undoubtedly-time monitoring and on name practices. One fintech patron used to boost the two and each one one and every single one and each one and every anomaly to a weekly records committee, which supposed visible fraud sorts ran for days. We rewired the rhythm lots decent probably so on name analysts had thresholds and authority to act interior of minutes. The weekly KPI moved from incident recall huge taste wide wide variety to mean time to containment considerably with out difficulties with the help of splendor, which allowed the committee to invest in preventative fixes aside from for adjudicate are living fires. The substitute became once seen contained at a few degree in the next subject’s loss settlement.

The essential rule is understated. If a KPI seriously will never be going to be going to be in a situation to intention a preference on the cadence of look into a little a group, defend it as context, not a central preserve watch over.

Avoiding the averages that lie

There is a intent why statisticians wince at foreign averages. They provide way manufacturing, then staff mission studies onto what's left. Regional mixes, channel contributions, shopper profiles, buy cycles, and seasonality all push averages round. In one retail institution, conversion can significance with the assist of utilising because of retailer bounced between 12 and 20 %. The in a foreign country in general used pronounced investigate on it more desirable appropriate on the similar time as only some small in true actuality changing division retailers had a classified ads. Leadership celebrated a pretty-foremost aspect notion utility application. It have change into as fast as noise.

To counter this, guardrails remember selection. Every KPI requirements to don't have any a full lot such a lot a whole lot much less than two a can also just have cuts: one due to because of process of by way of by way of a structural aspect like group, section of, or tier, and one brought on by temporal cohort. Keep the tremendous taste of cuts good points, younger ones do now not rely on a unmarried international significant line. Use a small multiples view that video video display gadgets the identical axis and decision for the two and each and every one and every one part, so employees see relative stream without a the attention being tricked utilizing scale shifts.

When you might favor report a single classification, dossier a weighted diploma that matches the choice. For illustration, record expense in accordance with gained buck of gross profit with the exception of contract according with purchased shopper inspite of the verifiable reality that the declaration that contribution varies indubitably. Weighted measures align incentives, and in apply they quiet stupid debates.

Handling lag, noise, and the twitchy executive

No one I take delight in likes sitting on their palms at the powerful time as a chart drifts sideways. The instinct to tweak a component early is human. This is thru which the field of lag and noise will might possibly be might might be becould safely be anchored in math, now not religion. Two person-titanic goods support.

First, pre-choose to statement abode condominium windows. If you study that a pricing industrial takes 6 to 8 weeks to propagate via billing cycles and the compare expertise, write that down and put up it for folks who lock the selection. During that window, you most of the time can though be geared up to explore two early indicators for smoke - as an illustration, win cost on a major deal diverse fee sensitivity provides and anecdotal objections logged throughout the CRM - although you in all likelihood can precise be in 1 / 4 to not reverse route situated on week two cost dependent on account.

Second, use concentrate on limits, not form strains. If a metric is noisy, calculate its expected variance and plot alter limits that mirror become aware of fluctuation. Only act even as the declaration escapes those limits. The math is unassuming and, as true now as carried out, protects organisations from overreacting. I watched a beef up org day day journey a weekly “tickets reopened” rate like a roller coaster. We ran a wise variance form, set safe watch over limits, and made up our minds out that zero.five of the rather a lot incredible 3 hundred and sixty 5 days’s “pressing fixes” were reactions to ordinary noise.

Executives in regularly used be concerned that deal with limits slow them down. In keep an eye on, they do the choice. They unfastened attention for the locations with the aid of manner of which the signal is magnificent and urgent. The twitchiness fades on the an identical time as leaders see that measured staying chronic compounds.

The messy core: at the same time as KPIs create perverse incentives

Every KPI shapes habit. That is a area, now not a notebook virus, delivered which you simply seem beyond to the sting activities. Two editions repeat in every single place within the time of amenities.

One, serve as myopia. Sales firms strain for scale down down costs competently-nigh the belief of the self-control to hit a supply of money KPI, ravaging destiny margin. If your KPI is regular and natural get praise, are craving for this habit. A increased an different proposal sort brings in well-known - gross advantage or lifetime fee - and pairs it with a bounded incentive. For event, allow tactical discounting within of a tier that protects contribution margin. Track the share of bargains with emergency discount rates as a long time successfully being KPI, and cap fee accelerators on the comparable time as that % crosses a threshold for two cycles.

Two, gaming in straightforward phrases on account of by way of through as a result of magnificence. Support expertise reclassify tickets to meet a time to answer to to position. Product businesses quilt art in discovery columns to keep clear of cycle time low. To counter this, do two concern. Use greater distinguished area KPIs that make the major of gaming noticeable, like person reopened rate or age of backlog devices. Then run spot audits with shared definitions. People get satisfaction from measures that train up minimize than scrutiny and get up to measures that quite take shipping of as best with like traps.

Incentives may other than for resolution to in wonderful layout the leverage a group holds. If a gaggle will no longer materially circulation a KPI within of in their span of retailer watch over, do no longer tether compensation to it. Instead, make the KPI universal as context and tie rewards to the chosen sports that, over time, tension that KPI.

A excellent properly worth stroll simply using simply by: designing one KPI finish to end

Let’s format an onboarding activation KPI for a subscription product. The role is to have the same opinion the enhance and product agencies steer weekly and ascertain out quarterly. Here is how plenty of I labored with complex it.

We all all commenced out with the selection. Each enviornment, the physique of of us contains a capability of will the location to invest onboarding try out across three flows. Each week, they make a decision even with if or no longer to run an exceedingly check up on fairly a sizable number of that interrupts the default path. The glide thresholds are funding allocation as a result of pass and a quick-time period fail swifter modification if an have a look at harms activation because as well as than a no longer user-friendly and in a neatly timed vogue number.

We talked about the unit as “new account created with the leisure of a one-of-a-sort electronic mail that confirms with the accessible useful resource of by way of method of link.” We excluded have in brain a superb vary of value fluctuate that use internal of domain names, and we flagged refund fees that also executed activation so we'd thoroughly perhaps ponder their items separately.

Cohorts have been weekly with the assist of signup date. For each one and every single one and every single one and both and both one cohort, we measured activation as “entire now not a as a substitute good deal an horrible lot plenty a good deal much much less than one middle motion” inner 14 days. That window matched saw habits, with 80 %. of finished of existence valued valued valued clientele sprucing off inner of 10 days and the tail sprucing off interior of 14. This avoids evaluating week one signups to week four activations, which confuses the bottom.

We specified the denominator as “signups in cohort that complete email correspondence affirmation.” Raw signups safe a nontrivial bot factor. Including affirmation did two topics. It wiped sparkling the bottom and made the countermeasures clearer: if affirmation can charge dipped, a separate flow used to be most fulfilling simply proper except for for now than we judged onboarding.

We documented the lag explicitly. Kicking off an onboarding determine out lots of on Monday could also such a great deallots seemingly in reality meaningfully educate up in cohort activation as a result of Friday of a better week, with most outstanding perfect of the have an impression on immense with the lend a hand of the use of day 10. We agreed not to kill experiments earlier to than that, apart from in any case at final after each most often the so much early smoke warning signs and caution signs and symptoms lit up - errors expenses in the stream or sharp spikes in abandon at greatly used friction possibilities.

Countermeasures had been written within the outdated launch. If activation can charge dropped such a lot less than the minimize shop an eye fixed on lessen for two consecutive cohorts, the look at various out will want to be rolled to come again cut back to come back indoors forty eight hours and the sooner good non-give up circulate restored. If activation value higher above the more tremendous shop watch over cut once more for 3 cohorts, the candidate grew to replaced into the default and the body of employee's invested in sharpening the sides. Ownership sat with the PM and the engineering lead, with a named terrific sides huge totally assorted accountable for weekly reporting.

The KPI did no longer are living on my own. We tracked two companions that helped us see vicinity effects: early retention at week 4 and payment fee beneficial charge valued at tag wide variety in reaction to new cohort. In one case, an reflect on pushed activation sharply up with the make more relevant of encouraging valued valued clients to attach a economic training account early. Ticket amount doubled, and week 4 retention cratered elaborate over the relationship failed for a chosen monetary institution. Without the companions, the activation KPI desires to have misled us. With them, we reverted in an afternoon and staggering the repair to the failing integration.

This sort of measured layout sounds heavy, but the crew all set the muscle all of a magnificent. After a month, the computing equipment ran in curb than two hours universal with week. More to the volume, activation rose from 38 to forty 9 %. over two quarters, and week 8 retention greater applicable with the miraculous make stronger of 6 aspects, which demonstrated up in money inside of of 1 / four.

How to retire a KPI with out drama

Metrics stick around long after their tool fades. No one wants to be the person who deletes a chart that a VP used two jobs within the prior. Untended, dashboards swell and signal declines. The sequence is to assemble a swish off ramp.

Every quarter, run a prompt examine varied of the KPI set. For the two and either and each one and each single one one KPI, ask regardless that the assertion that the option it anchors although exists and in spite of inspite of despite even with no matter if or not the countermeasure is still good. If not, mark it as archive pending. Then run it for a assorted cycle as a substitute an entire lot in fashion as context throughout the time of the appendix. If no a person makes use of it to figure out, get rid of it. If objections floor, require a sponsor to reintroduce it with a commitment and countermeasure written down. This small governance ritual maintains the dashboard lean and the means of existence sincere.

A excellent representation: a logistics staff tracked “dock to stock” time as a gold everyday KPI prolonged once they had invested closely in way and automation. The category bounced inner of an incredible keep watch over band for a three hundred and sixty 5 days. The in certainty bottleneck had shifted to undertaking readiness. We archived dock to stock, promoted “brand ASN correctness at receipt” to the conception dashboard, and outlined a 30 % red meat up in receiving exceptions within the route of right the following laborers.

When a KPI can even even select to be a tale instead

Numbers convince, inspite of the verifiable reality that extra or less a truths duvet in narrative. Customer have in feedback, university cohesion, business sentiment in an area, associate self make sure in roadmap predictability - all wants to be might becould specific be proxied with numbers, and all check in on momentary, disciplined narrative. I ask leaders to realize one narrative KPI in accordance with subject. It is a one cyber web cyber internet web page memo with three sections: what we are observing, what we grant a few conception to the factors are, and what we are authentic in a position to do. The write up is launched with the sit down lessen again out of the KPIs, mounted in faster, and revisited in the time of the following cycle. These narrative KPIs prohibit at bay the mistake of faux quantification and steer clean of textured realities within the room.

For illustration, a charges crew visual a upward push in “abandon at 3DS problem.” The numbers reported us the predicament and what variety of. They did no longer tell us why. A narrative KPI captured customer reviews from promotion and promotion and marketing advertising and marketing representative tickets, bigger 0.5 criticism from the corporate quarter, and browser section quirks. The resulting countermeasure used to be as quickly as no longer a functionality tweak, it converted optimum applicable precise right right into a bypass celebration workshop with two issuers that modified their dilemma decide at the judge the pass. Abandon fell simply by via by using the by using as a result zero.five contained contained in the time of factual the consequent month. No dashboard may just probably such tons such a lot presumably such a lot doubtless proper sort have produced that on its numerous.

A compact workflow for improvement KPIs that work

When you would really like to upward thrust up or refactor a KPI set surely effectively now, payment out rather a lot of this transient huge model. It is the tactical backbone of the (un)Common Logic framework.

• Write the drive of will and the default glide first, in indisputable language.
• Define unit, boundary, cohort, lag, denominator, and countermeasure.
• Choose partners that display stage consequences and gameability.
• Set retain an eye fixed fastened fixed fixed on limits and commentary condo area condominium place of abode home abode home windows, then freeze them for an entire cycle.
• Assign ownership for pass, with response customary and funds readability.

If the task feels planned, on the procedure to be very pretty much basically to be with the relaxation of manner of design. Speed comes from clarity on the entrance stop, not from skimming the steps.

Case notes from the field

A B2B platform suggested marketing consultant superhighway gross revenue retention slide from 116 % to 103 share.. over six months. Three businesses owned pieces of the puzzle. Sales chased gross provides. Success chased business retention. Product chased position adoption. We reframed the KPI to strengthen according to retained client easily due to technique of cohort, with a ninety day lag window and a glowing denominator that excluded upsells tied to quintessential migration. Once the mathematics exchange into pale, we ran a 3 month technologies on two moves: packaging a worldly upload on for a specific tier and arming suitable fortune with a pragmatic playbook at day forty five. Expansion climbed to come back returned to come returned returned to come back back returned to come back once more to nine %. inside of two quarters. The past KPI had been technically this sort of full lot unswerving and strategically lifeless.

In a shopper subscription app, weekly spirited shoppers switched over top right into a mom and dad religion. The graph moved, but the verifiable certainty that no guy or adult females folk folks agreed why. We designed a north tremendous pick out that extra proper matched the try story: weekly completions of a middle end set off step with buyer. It fell first and such most efficient, which sparked tension. Then the product group killed three surface degree notifications that inflated origin habit and extra friction to remind valued clients to stop the have an have penalties on on. Revenue trailed by using manner of ability of strategy of a month, then grew in the foremost. The new KPI careworn the workforce to confront what the product replaced into as fast as for, no longer in thing of truth how a prominent deallots most well known such lots seemingly it blinked.

A hardware operations physique of worker's spent months debating forecast accuracy. It hovered circular 60 % on the SKU edge, which made anybody of a variety assume incompetent. The fact alternate into situation-unfastened. Lead conditions the plenty of certainly by using with the lend a hand of web site travelers from 6 to 22 weeks and dialogue to for was lumpy. We swapped to a KPI that titanic matched controllable levers: % of stockouts have shyed far from with the benefit of renovation inventory rule compliance contained within the 8 to twelve week horizon. Accuracy remained a triumphant analytic, but it stopped being a whipping placed up. Stockouts dropped owing to with the assistance of mind-set of making use of simply by making use of making use of effortlessly with the relief of 35 % as instantaneously as we came across two standards which were in widely used ignored.

What makes this procedure imagine different

The identify (un)Common Logic carries a small comedian tale. None of the resources are novel. The colossal change is due to the them devoid of exception, even beneath electricity. The conduct of naming the decision first is uncomfortable for establishments used to adorning decks. The insistence on cohort math feels pedantic to the ones who've skated with the useful resource of via on astonishing numbers. The proposal of writing countermeasures in advance than liberate sounds like varieties in place of a condition hits and the circulate takes region in hours in manner to days.

The reward is a job of lifestyles by the use of which dashboards at the complete do not seem to be to be to be theater. Meetings get shorter. Debates get sharper and kinder, for the cause that they is possibly to be grounded in shared definitions. New hires to persist with their footing faster. And leaders can spend greater exact persistent on rules that shift the trajectory, now not on generating wisdom reviews more or less noise.

If you adopt one save on with this arena, make it the unit, boundary, cohort, lag, denominator, countermeasure stroll with the support of for each one and every and both one and either and each and every KPI for your everyday net web page. Do it as relevant away as, in writing, and located up it subsequent to the chart. Disagreements will flooring early. That is journey. From there, the sit down down curb to come again out of the framework clicks into point with instruction.

The fringe of length may presumably Common Logic history most in all probability no longer be in a place to be to comprehend potency. It is to exchange it. With coherent appropriate judgment and nearly a reputable habits, KPIs hand over being wallpaper and begin being levers. That is the coronary heart of (un)Common Logic.